Atmospheric Factors Controlling the Stable Isotopes (δ18o and Δ2h) of the Indian Summer Monsoon Precipitation in a Drying Region of Eastern India

•Atmospheric controls on the isotopic content of rain in East India were evaluated.•Isotopic composition of rain is not correlated with hydrometeorological parameters.•Convective activity plays a key role in evolving δ18O & δ2H of rain in East India.•Sources of moisture for ISM rains in drying regions of East India were identified.