PUNE: A study by the National Environmental Engineering Research Institute ( Neeri ) in Nagpur has found a “very strong” correlation — up to 85% — between the increase in the average day temperature and the reduction in Covid-19 spread for select cities in the country and for states like Maharashtra and Karnataka as a whole.Neeri, a constituent laboratory of the Council of Scientific and Industrial Research, based its research on a mathematical model. It sourced Covid-19 case data from the World Health Organisation and temperature data from India Meteorological Department . It studied the average real time temperature and relative humidity and their relationship with the rising Covid-19 cases in Maharashtra and Karnataka.The Neeri research said when the gross values of temperature and relative humidity were considered for these two states, an increase in the average day temperature from 25°C and above caused a reduction in Covid-19 cases.However, the study pointed out that while the hot climate in India may prove to be beneficial in containing the Covid-19 spread, social distancing measures far outweighed the benefits of environmental factors like temperature and humidity.Hemant Bherwani, scientist in the director’s research cell at the Centre of Strategic Urban Management, Neeri, told TOI, “We did not want to only focus on temperature and humidity and their effect on the Covid-19 spread.Therefore, we also included social distancing in the research. Covid-19 is a highly contagious disease and India a very populous country. Therefore, unless social distancing is followed, the benefits of aspects like high temperature may not be visible.”