Wildfires and heatwaves, which generate microscopic airborne pollutants, risk undermining international efforts to improve air quality, protect human health and safeguard nature, the World Meteorological Organization (WMO) said on Monday (September 7, 2026).

The United Nations’ weather and climate agency underlined the links between air pollution and climate change, which scientists say is leading to more frequent and more intense heatwaves and wildfires.

“Extreme wildfires are increasing, leading to big health consequences because of the high toxicity of smoke,” the WMO said in a statement accompanying its latest annual Air Quality and Climate Bulletin.

“Whilst regulations in Europe and North America have reduced industrial and transport PM2.5 emissions, exposure to fire-related PM2.5 has increased.” the statement added.

Particulate matter PM2.5 is composed of microscopic particles and droplets of less than 2.5 micrometres in diameter, which is a health hazard because it can penetrate deep into the lungs and bloodstream.

It is emitted by fossil fuel-driven industrial activities, farming, domestic heating and transport, as well as by wildfires and dust storms.

The report said the world needs to better monitor air pollutants such as aerosol, including black carbon and microplastics, fine particles and ground-level ozone.

These pollutants “are not sufficiently monitored even though they are widespread and are potentially harmful to ecosystems”, the WMO said. “(We need) complementary and coordinated policies on air quality and climate because they cannot be dealt with in isolation.”

Toxic wildfire smoke

“Air quality and climate change can’t be dealt with separately. If one worsens, the other does too,” Lorenzo Labrador, from the WMO’s Global Atmosphere Watch network of scientists, told AFP.

Also read: Warning on warming: On the UNEP report, Limiting Overshoot

“In places where there are relatively powerful forest fires, we find a lot of fine particle pollution,” he said.

“Microparticles generated by burning vegetation are much more toxic than those emitted by other sources, even car exhaust,” he stressed.

“They damage the health of people and wildlife living far from the fire itself because they are carried by the wind, but their poisonous effect is not sufficiently taken into account in air quality assessments,” Labrador said.

“Conventional risk models based on total PM2.5 concentrations may underestimate wildfire-attributable mortality by up to 93%,” the WMO said.

One study cited in the WMO Bulletin says extreme fire-smoke events have tripled globally since the 1990s, contributing to nearly 100,000 additional deaths per year between 2010 and 2018, although this may be an underestimate.

Ozone, microplastics

Another source of air pollution that carries major health risks is ground-level ozone, which accumulates when temperatures rise, atmospheric conditions stagnate and solar radiation is intense, as seen during recent heatwaves in China, Europe and the southeastern United States.

“This increased exposure to ozone pollution has the potential to lead to tens of thousands of additional premature deaths,” particularly due to respiratory diseases, the WMO warned.

Another growing concern is aerosol particles, which can also travel to oceans and continents far from their source.

They can alter the way the atmosphere reflects sunlight, change the chemical properties of land and water, and pollute otherwise clean environments.

“One example is the deposition of black carbon, or soot, on snow and ice, which reduces the amount of sunlight reflected by these surfaces and in turn can hasten the melting process,” the WMO explained.

Another example is microplastics, formed when plastics break down because of sunlight or other factors, and found virtually everywhere, in the air, the soil and the oceans.

One simulation in the WMO Bulletin estimates there are “51 million tonnes for land and 22 million tonnes for the ocean, which are in turn a source of microplastics for the atmosphere”.

“As plastic production and, critically, mismanaged plastic waste continues to increase, monitoring the airborne paths that carry microplastics from their source and dump them in remote environments will be crucial”, the report said.

Published – September 07, 2026 10:36 am IST

A thick blanket of smog is hovering over two metropolitan cities, Delhi and Mumbai, as the air quality dipped amid cold wave conditions. The Air Quality Index (AQI) in the national capital stood at 386 in the ‘very poor’ category for the second consecutive day on Sunday morning, while in Mumbai, it was 176 in the ‘moderate’ category.

An AQI between 0 and 50 is considered good, 51 and 100 satisfactory, 101 and 200 moderate, 201 and 300 poor, 301 and 400 very poor, 401 and 450 severe, and above 450 severe-plus.

Delhi air quality

Delhi has been yet again witnessing deteriorating air quality this week, forcing authorities to re-impose the fourth and last stage of the Graded Response Action Plan (GRAP). Under this, all schools are shifted online and a ban is imposed on Delhi-registered BS-IV or older diesel medium and heavy goods vehicles. All the construction activities in the national capital are also halted.

On Monday, Delhi’s AQI breached the 400 mark and dipped into the ‘severe plus’ category. According to the India Meteorological Department (IMD), the smoggy conditions may persist for a few more days as the cold wave in the national capital is intensifying.

The AQI on Saturday stood at 370 in the ‘very poor’ category, with the visibility dropping in the national capital. The Delhi Airport also issued an advisory for passengers saying, “Low visibility procedures are in progress at Delhi Airport. All flight operations are presently normal. Passengers are requested to contact the airline concerned for updated flight information.”

Update issued at 07:20 hours.
Kind attention to all flyers!#Fog#FogAlert#DelhiAirportpic.twitter.com/0AWazsi9y8

— Delhi Airport (@DelhiAirport) December 21, 2024

Mumbai air quality 

Mumbai has been witnessing its coldest winters in decades, pushing its air quality down. For the fourth consecutive day, the city was shrouded in a blanket of smog with the overall AQI touching 176. Earlier this week, the AQI also touched 199 in the ‘poor’ category.

Several citizens posted videos and pictures on social media showing the worsening air quality in Mumbai.

What’s with Mumbai. Pollution or fog. It was the same yesterday..#mumbaiweatherpic.twitter.com/mYzwdquGou

— Manda Bendre (@mabend2) December 21, 2024

Some visuals also showed the Bandra-Worli Sea Link vanished due to the smog.

China was once nicknamed as the “Kingdom of Bicycles” because of the widespread practice of cycling in this densely populated nation. There was a time when a bicycle was one of the “three rounds” every Chinese house desired, together with a wristwatch and a sewing machine.

However, the country has faced many challenges since it transitioned from bicycles to automobiles and other combustion engines. This shift led to complex problems for the environment, society, and economy. Beijing became known specifically for its poor air quality and a lot of haze.

The fast-growing population, along with high vehicle count and economic expansion, causes this much pressure on Beijing’s ecology.

Despite these obstacles, Beijing has improved its air quality significantly in recent years, serving as a model for other cities, particularly in South Asia, facing comparable problems.

As China emerged as the world’s largest automobile producer and consumer, it grappled with the detrimental impacts of increased oil consumption, but now China’s skies are clearer, and its air quality has drastically improved.

According to the World Economic Forum, the Chinese capital has cut fine particle pollution by 64% and sulphur dioxide by 89% since 2013-now other cities are following its lead.

According to a UN report, Beijing has implemented a “coal-to-gas” policy since 2005 and reduced coal combustion by nearly 11 million tonnes by 2017. High-efficiency terminal treatment facilities were continuously renovated, and ultralow emission standards were enforced during this period.

The prevention and control of vehicle pollution have long been critical tasks in Beijing’s air pollution control. Focusing on new vehicles, in-use vehicles, and fuel quality, Beijing has implemented a series of local emission standards and comprehensive control measures, as well as strengthened traffic management and economic incentives continuously.

Although the number of vehicles increased threefold in Beijing during the last two decades, the total pollutant emissions decreased remarkably.

With Delhi’s air quality plummeting to “severe+” for the first time this season, the Centre’s air quality panel on Sunday announced stricter pollution control measures for the Delhi-NCR under Stage 4 of the Graded Response Action Plan (GRAP), which will come into effect from 8 am on Monday.

The restrictions include a ban on truck entry and a temporary halt on construction at public projects.

“The AQI of Delhi was recorded at 441 (Severe) at 4:00 PM today and has been gradually increasing further and has already reached Severe+ category, as thc AQI clocked 447, 452 and 457 at 5:00 PM, 6:00 PM and 7:0O PM, respectively,” said the Commission for Air Quality Management (CAQM), the Centre’s panel on Delhi-NCR air quality.

The GRAP for Delhi-NCR is divided into four stages of air quality: Stage 1 for “poor” air quality (AQI ranging from 201 to 300), Stage 2 for “very poor” air quality (AQI from 301 to 400), Stage 3 for “severe” air quality (AQI from 401 to 450), and Stage 4 for “severe plus” air quality (AQI above 450).

Delhi Chief Minister Atishi announced that physical classes will be discontinued for all students, apart from Class 10 and 12, in view of the rising pollution.

With the imposition of GRAP-4 from tmrw, physical classes shall be discontinued for all students, apart from Class 10 and 12. All schools will hold online classes, until further orders.

— Atishi (@AtishiAAP) November 17, 2024

According to the order, no trucks will be allowed into Delhi except for those carrying essential items or using clean fuel. 

Non-essential light commercial vehicles registered outside Delhi will also be prohibited, except for Electric Vehicles and CNG and BS-VI diesel ones.

Delhi-registered BS-IV or older diesel medium and heavy goods vehicles are banned, except for those in essential services, the panel said.

All construction activities, including highways, roads, flyovers, power lines, pipelines and other public projects, have been suspended.

The CAQM suggested online teaching for the students of Classes 6 to 9 and Class 11.

It also recommended that offices in the National Capital Region (NCR) work at 50 per cent capacity, with the rest working from home.

Work-from-home options may be introduced for central government employees, the panel said.

State governments could also decide to close colleges, limit non-essential commercial activities and implement odd-even vehicle rules, it said. 

New Delhi:

A thin layer of smog engulfed the national capital and the AQI was recorded at 296 at 7 am on Saturday, according to the System of Air Quality and Weather Forecasting and Research (SAFAR).

In Anand Vihar, the AQI was recorded at a very poor category of 380 at 7 am; in ITO, it was 253 (poor) at 6 am; in RK Puram, it was 346 (very poor) at 6 am; in IGI Airport T3 it was 342 (very poor) at 6 am; and in Dwarka Sector 8 the AQI was 308 (very poor) at 7 am, according to the Central Pollution Control Board (CPCB).

In Anand Vihar the AQI was recorded in the very poor category of 380 At 7 am, in ITO Delhi at 6 am poor 253, in RK Puram at 6 am very poor 346, in IGI Airport T3 very poor 342 at 6 am, in Dwarka Sector 8 AQI was recorded in very poor category at 308 at 7 am.

A cyclist near India Gate told ANI that air pollution makes breathing difficult while cycling, jogging, or engaging in heavy physical activities.

“There are serious problems because of pollution; if you look around, the air is polluted. When you walk normally, you don’t feel it, but if you cycle, jog, or do any heavy work, you will feel that it is quite difficult to breathe,” a cyclist told ANI.

Another cyclist mentioned that pollution levels will rise further in the coming days, and there won’t be any relief.

“The pollution level will rise after 2-3 days. There won’t be any relief (from pollution), but it will increase,” he told ANI.

On Friday a day after the Diwali celebration, the city’s air quality was recorded in the ‘very poor’ category, according to the Central Pollution Control Board (CPCB). Most areas in the capital recorded an Air Quality Index (AQI) over 350, raising health concerns for residents.

At around 7:00 am, Anand Vihar recorded an AQI of 395, Aya Nagar stood at 352, Jahangirpuri at 390, and Dwarka reached 376. All these areas reported ‘very poor’ air quality levels, posing significant health risks.

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)

Delhi:

Delhi’s air quality improved slightly on Saturday morning nearly four days after the national capital reeled under toxic air pollution, however, it still remains in the ‘poor’ category. The Air Quality Index (AQI) in Delhi dropped to 230 this morning – from Friday’s reading of 270. 

According to the Air Quality Early Warning System (AQEWS), the air quality in Delhi has improved due to a sudden change in wind direction and speed. Despite the improvement, weather experts have cautioned that the relief may be short-lived, as pollution levels are expected to rise again in the next three days, reported news agency PTI.

The air quality index is likely to touch 400 by October 31, the weather system said. 

Fearing further air quality deterioration after Diwali, the Delhi government has imposed stage two of the GRAP or the Graded Response Action Plan. Under this stage, there are restrictions on the use of coal, firewood, and diesel generator sets across Delhi-NCR. The administration will carry out mechanical sweeping and water sprinkling on roads daily, while people have been advised to use public transport and minimize the use of personal vehicles.

On Friday, Delhi Environment Minister Gopal Rai conducted a demonstration showcasing drone-based services to identify sources of pollution in hotspot areas. He also discussed the recently released 21-point Winter Action Plan designed to tackle various pollution sources, including dust, vehicle emissions, and open burning, reported PTI.

“The Delhi government is working tirelessly day and night to combat pollution,” he said.

According to Delhi Mayor Shelly Oberoi, the civic body has formed 372 surveillance teams to monitor pollution. A total of 57,000 sanitation workers have been deployed for manual sweeping on the roads, while 195 water sprinklers and jetting machines have been stationed across the national capital. Thirty anti-smog guns have also been installed at polluted locations identified by the Delhi Pollution Control Committee (DPCC), the Mayor said.

Some of the neighbouring states are witnessing a poor air quality index – Uttar Pradesh at 254 AQI, Haryana at 267 AQI, and Rajasthan at 243 AQI.