Researchers from IIT Kanpur had warned the Central Pollution Control Board (CPCB) in early October that Delhi was headed for a spike in pollution between October 28 and November 4 and had strongly recommended immediate measures to ward off the crisis,has learnt. They had submitted a study, based on modelling of Delhi’s air quality and meteorological data in early October, recommending that a number of measures be taken as soon as Air Quality Index (AI) hits 200.Identifying October 29-November 12 as peak period for increase in PM 2.5 concentration, the study, a copy of which was seen by ET, said “we need to somehow avoid this situation in 2019. Acting after-the-fact can bring restricted air quality benefits… Reacting after-the-fact will be nearly futile and we will watch the situation helplessly except for praying nature’s intervention,” it said.The study – authored by Prof Mukesh Sharma, who also did the first authoritative study on sources of Delhi air pollution in 2016 – suggested steps to ensure farm fires are brought down to less than 1,000, efforts be made at panchayat and block levels to not burn biomass at all and road cleaning be such that silt loading is less than 2gm/m2 on Delhi’s roads.The study suggested that the CPCB’s Graded Response Action Plan (GRAP) be implemented fully during October 24-November 15 and not wait for PM2.5 levels to go above 250 µg/m3.“The GRAP has all the actions that will improve the air quality and reduce the emission to desired levels. But these actions are to be taken during October 24 to November 15, regardless of air quality in this period in an area up to 75 km from Delhi in all directions,” said the study.The study said that much more should be done even as the AQI had improved in 2017 and 2018 from that in 2016, with ‘severe’ category days reducing to 4% in 2018 from 24% in 2016, partly because of higher wind speeds in 2017 and 2018 as well as actions taken to reduce crop residue burning.