The Indian government has set an ambitious target for future renewable power generation, including 60GW of cumulative wind power capacity by 2022. The benefits of such significant investments are vulnerable however to changing climate. Based on hourly wind data from an assimilated meteorology reanalysis dataset covering 1980-2016, we show that wind power potential may have declined secularly over this interval, particularly in western India. Surface temperature data confirm that significant warming occurred in the Indian Ocean over the study period, leading to modulation of high pressure over the ocean. A multivariable linear regression model incorporating the pressure gradient between the Indian Ocean and the Indian subcontinent can account for the inter-annual variability of wind power. A series of numerical sensitivity experiments confirms that warming in the Indian Ocean contributes to subsidence and dampening of upward motion over the Indian continent, resulting potentially in weakening of the monsoonal circulation and wind speeds over India.