Air pollution is choking several cities in the northern States once again, as changes in temperature and slowing winds trap soot, dust and fine particulate matter. The National Capital Region is badly hit, as the burning of agricultural residue in Punjab and Haryana is releasing large volumes of smoke containing, among other pollutants, highly damaging fine particulates, or PM2.5. The problem is aggravated by the burning of urban waste, diesel soot, vehicular exhaust, road and construction dust, and power generation. Although India has nine of the 10 most polluted cities in the world, it has not taken consistent action on pollution. Tens of millions live with ambient air quality that is well short of even the relaxed parameters the country has set for fine particulates, compared with those of the World Health Organisation. India should at least now give high importance to the WHO warning about air pollution being the new tobacco. This year’s ‘severe’ air quality rating for Delhi and poor conditions prevailing in other cities in the Indo-Gangetic Plain should compel a decisive shift in policy. The Centre and the State governments need to get into crisis mode to dramatically reduce emissions. They must address the burning of carbon, which is a direct source, and emissions with oxides of nitrogen and sulphur from vehicles that turn into fine particulates through atmospheric reactions. Failure to take sustainable and urgent measures will inflict long-term harm on public health, affecting children even more by putting them at higher risk for diseases.