Controlling the spread of Covid-19 in India may become a greater challenge with the progression of the season towards monsoon, post-monsoon, and thereafter, winter, with a continuous fall in temperature, claims a study conducted jointly by researchers at IIT-Bhubaneswar and AIIMS-Bhubaneswar.Every degree rise in temperature corresponds to a 0.99 per cent decrease in the number of cases and an increase in doubling time by approximately 1.13 days, implying a slowing down of spread, said the study titled "Covid-19 spread in India and its dependence on temperature and relative humidity".The study, led by V. Vinoj, Assistant Professor of the School of Earth, Ocean and Climatic Sciences at IIT-Bhubaneswar, examined Covid-19 outbreak patterns and cases in 28 states between April and June.Particularly, they focused on the relationship between Covid-19 spread and environmental factors such as temperature, relative humidity, specific humidity, and solar radiation.The results showed that temperature and relative humidity have a significant impact on the disease growth rate and doubling time, according to the abstract of the study posted on ResearchGate, a professional network for scientists and researchers.The study is currently at pre-print stage and yet to be peer-reviewed.An analysis for relative humidity revealed that more moisture leads to a higher growth rate of Covid-19 cases and reduced doubling time, said the study.Lower specific humidity and higher surface-reaching solar radiation reduced the spread and increased the doubling time similar to that of temperature, the results showed.The researchers noted that past respiratory viral pandemics of the 21st century revealed seasonality in environmental factors to play a role in the dynamics of their spread.The study comes at a time when daily Covid-19 cases are setting new records.India's total coronavirus cases have already surpassed 1 million, with a record 38,902 new cases reported in the past 24 hours.With 543 new deaths, the total death toll stood at 26,816 on Sunday.