MUMBAI: Air pollution contributed to a total of 80,665 premature deaths of adults over 30 years in Mumbai and Delhi in 2015, a two-fold jump from 1995, according to a new study at the Indian Institute of Technology, Bombay.In economic terms, air pollution cost the two cities $10.66 billion (approximately Rs 70,000 crore) in 2015, or about 0.71 per cent of the country's gross domestic product The study has said the impact on health and productivity as a result of exposure to pollution and the consequent burden of respiratory ailments rose with every passing decade.Researchers calculated impact using data on PM 10 (fine particulate matter measuring 10 microns), population and death rates.With its higher pollution levels, Delhi recorded more premature deaths due to ingestion of PM10 from vehicle exhaust, construction dust and other industrial processes. Casualties went up from 19,716 in 1995 to 48,651in 2015. In Mumbai, the comparative figure rose from 19,291 to 32,014 in 20 years.Air pollution was also responsible for 23 million cases of restricted activity days (RAD) — either less productive days or days off work for individuals — in the commercial capital in 2015.The worsening quality of air in the city also led to 64,037 emergency room visits in 2015 by those stricken by respiratory ailments, up by 35.4 per cent from 1995. In comparison, in Delhi, there were 29 million cases of RAD and 0.12 million emergency room visits in 2015.The study's lead author, Kamal Jyoti Maji, said the impact of air pollution on health and productivity was evident in that the increase in cases and cost after 2005 was in line with the overall trend in pollution.Pollution also cost the two cities as much as $10.66 billion in 2015, or about 0.71 per cent of the country's GDP, a cost that's almost doubled since 1995.The economic cost of PM10 exposure rose by around 60 per cent in Mumbai from $2.68 million in 1995 to $4.26 billion in 2015. Cost to Delhi jumped by 135 per cent in the same period to hit $6.39 billion, the study found.One measure of health and longevity is called "disabilityadjusted life years" (DALY), representing years lost due to various illness. This measure for illnesses caused by air pollution doubled in Delhi between 1995 and 2015 from 0.34 million to 0.75 million DALY. In Mumbai, that number rose from 0.34 million to 0.51million DALYs in the same period. To keep to current health outcomes in 2030, PM10 levels would have to decline by 44 per cent in Mumbai and 67 per cent in Delhi, the study said.These estimates are likely to be an undercount of actual costs, mortality and morbidity, said the researchers, since the study looked only at the impact of PM10 and to a lesser extent PM2.5. The IIT study was published recently in the Environmental Science and Pollution Research Journal, and authored by research scholar Maji, IIT Bombay professor Anil Dikshit and Ashok Deshpande from the Berkeley Initiative in Soft Computing, USA. In India , air pollution causes over half a million premature deaths annually and 20 million DALYs, according to WHO.