01.04.2026 17:18
According to a report published by the Swiss air monitoring agency IQAir, the world's dirtiest capital for the eighth consecutive time is New Delhi, the capital of India. The report states that Central and South Asia are home to 17 of the 20 most polluted cities.
The Swiss air monitoring agency IQAir reported that only 14% of nearly 10,000 cities remain within the safe limits set by the World Health Organization, and that New Delhi, the capital of India, is the world's most polluted capital.
According to the 2025 World Air Quality Report published by IQAir, data collected from 143 countries and 9,446 cities highlights the critical importance of increasing investments in renewable energy and transitioning to clean energy in the fight against air pollution.
THE WORLD'S MOST POLLUTED CAPITAL: NEW DELHI
In New Delhi, where electricity production is largely based on fossil fuels, a significant portion of electricity is supplied from the national grid, reflecting a structure parallel to the country's dependence on fossil fuels.
Accordingly, only 13 countries and regions worldwide can meet the annual PM2.5 limit value of 5 micrograms per cubic meter (µg/m³) set by the World Health Organization. PM2.5 refers to fine particulate matter in the air with a diameter of less than 2.5 micrometers, and these particles can reach the lungs through respiration, leading to serious health risks in the long term.
New Delhi has maintained a high pollution level with an annual average PM2.5 level of 82.2 µg/m³ in 2025, making it the world's most polluted capital for the eighth consecutive time.
CENTRAL AND SOUTH ASIA STANDS OUT IN AIR POLLUTION
The capital of Bangladesh, Dhaka, with 68.0 µg/m³, the capital of Tajikistan, Dushanbe, with 57.3 µg/m³, and the capital of Chad, N'Djamena, with 53.6 µg/m³, were among the most polluted cities.
On the other hand, among the capitals with the best air quality, Papeete from French Polynesia ranked first with a level of 1.5 µg/m³, while San Juan, the capital of Puerto Rico, had 2.3 µg/m³, and Bridgetown, the capital of Barbados, had 2.6 µg/m³, placing them high on the list.
Ankara's air quality was evaluated at 80th place with an annual average of 11.4 µg/m³ PM2.5.
ENVIRONMENTAL FACTORS AFFECT AIR QUALITY
The report also addressed the impact of environmental factors on the deterioration of air quality in 2025. It was noted that the intense particulate matter released into the atmosphere by record-level forest fires in Canada and Europe negatively affected global air quality.
In the assessment of the sources of air pollution, the use of fossil fuels, industrial activities, transportation, and energy production emerged as the main elements. Residential heating, agricultural burning activities, and the use of low-quality fuels were also among the factors increasing pollution, especially in developing countries.
Additionally, the increasing energy demand of artificial intelligence data centers and the use of diesel generators were highlighted as a new source of emissions. Among natural resources, it was emphasized that forest fires, dust storms, and volcanic activities also have an impact on air quality.
The report indicated the importance of cleaner sources in energy production for achieving lasting improvements in the fight against air pollution, noting that increasing investments in renewable energy not only reduces emissions but is also an important tool in mitigating environmental and health risks.