Ozone has emerged as a dominant pollutant along with particulate matter on at least 28 days during summer of 2019 as opposed to only 17 days in 2018 summer, says an analysis by Centre for Science and Environment (CSE).

TDS is made up of inorganic salts as well as small amounts of organic matter. As per a WHO study TDS levels below 300 mg per litre are considered to be excellent, while 900 mg per litre is said to be poor and above 1200 mg is unacceptable.