Delhi world’s most polluted capital for 6th straight year: Report

Thirteen of the world’s top 20 most polluted cities are in India, with Byrnihat in Assam topping the list, according to a new report published on Tuesday.

The World Air Quality Report 2024 by Swiss air quality technology company IQAir said Delhi remains the most polluted capital city globally, while India ranked as the world’s fifth most polluted country in 2024, down from third in 2023.

Four cities in neighbouring Pakistan and one in China are among the world’s top 20 polluted cities.

The report said India saw a 7 per cent decline in PM2.5 concentrations in 2024, averaging 50.6 micrograms per cubic metre, compared to 54.4 micrograms per cubic metre in 2023. Yet, 13 of the world’s 20 most polluted cities are in India.

Air pollution in Delhi worsened, with the annual average PM2.5 concentration rising from 102.4 micrograms per cubic metre in 2023 to 108.3 micrograms per cubic metre in 2024.

The Indian cities in the world’s top 20 most polluted cities are Byrnihat, Delhi, Punjab’s Mullanpur, Faridabad, Loni, Gurugram, Ganganagar, Greater Noida, Bhiwadi, Muzaffarnagar, Hanumangarh and Noida.

Overall, 35 per cent of the Indian cities reported annual PM2.5 levels exceeding 10 times the WHO limit of 5 micrograms per cubic metre, the report said.

The high level of pollution in Byrnihat, a town on the border of Assam and Meghalaya, is due to emissions from local factories, including distilleries, iron and steel plants.

Delhi grapples with high air pollution year-round and the problem worsens in winter when unfavourable meteorological conditions, combined with vehicular emissions, paddy-straw burning, firecrackers and other local pollution sources, make the air quality hazardous.

Air pollution remains a serious health risk in India, reducing life expectancy by an estimated 5.2 years.

According to a Lancet Planetary Health study published last year, about 1.5 million deaths in India every year from 2009 to 2019 were potentially linked to long-term exposure to PM2.5 pollution.

PM2.5 refers to tiny air pollution particles smaller than 2.5 microns, which can enter the lungs and bloodstream, leading to breathing problems, heart disease and even cancer. Sources include vehicle exhaust, industrial emissions and the burning of wood or crop waste.

Former WHO chief scientist and health ministry advisor Soumya Swaminathan said India has made progress in air quality data collection but lacks sufficient action.

“We have the data; now we need action. Some solutions are easy like replacing biomass with LPG. India already has a scheme for this, but we must further subsidise additional cylinders. The first cylinder is free, but the poorest families, especially women, should receive higher subsidies. This will improve their health and reduce outdoor air pollution,” she told in an interview.

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In cities, expanding public transport and imposing fines on certain cars could help. “A mix of incentives and penalties is necessary,” she said.

“Finally, strict enforcement of emission laws is crucial. Industries and construction sites must comply with regulations and install equipment to cut emissions instead of taking shortcuts,” the former director general of the Indian Council of Medical Research added.