Sir — This refers to the editorial, “Air most foul” (May 4). According to data released by the World Health Organisation, India accounted for 14 of the most polluted cities in the world in terms of small particulate matter measuring 2.5 microns. This is a worrying statistic and the overall picture of the quality of air in the country is not rosy. One fails to understand as to why air pollution was not included in the mission guidelines of the Swachh Bharat Abhiyan. Nevertheless, quick remedial measures must be initiated. We must plant as many trees as possible. At the same time, efforts must be on to control vehicular pollution and public transport system must be encouraged.