Nearly 15,000 people died prematurely in Delhi due to pollution by fine particulate matter in 2016, according to a new study which ranked the national capital third in a list of cities reporting most deaths due to air pollution.

Shanghai was ranked first in most premature deaths at 17,600 and Beijing second with 18,200 deaths due to PM2.5 pollutant. PM2.5 refers to atmospheric particulate matter with diameter less than 2.5 mm. "Air pollution is emerging as the main threat and to overcome it there is a need for a strong air quality management system and the Environment Ministry is finalising a National Premier Action Plan to fight air pollution in Delhi," said Anumita Roychowdhury, director at the Centre for Science and Environment.

PM2.5 has been associated with significant health effects, including cardiovascular diseases, lung diseases, cancer and premature deaths. The PM2.5-related health impacts are notable for megacities across the globe, but Asian megacities have been suffering much more, the study said. The phenomenon of smog-hit cities became so common recently that the term airpocalypse' has become synonymous with polluted air, it said.

This study reports PM2.5-related long-term mortality for the year 2016 in 13 megacities of China, India, Bangladesh and Pakistan using an integrated exposure risk (IER) model. In Indian megacities, the premature deaths were 14,800, 10,500, 7,300, 4,800 and 4,800 in Delhi, Mumbai, Kolkata, Bangalore and Chennai respectively. Though China has taken initial steps with pollution control targets and strategy, there was an urgent need for government policy in India, Bangladesh and Pakistan, the study said. This study highlighted the need for setting up decisive air quality targets by megacity authorities and advocates for joint regional efforts to control air pollution.