The COVID-19 lockdowns drastically reduced human activity, emulating a controlled experiment on human-land-atmosphere coupling. Here, using a fusion of satellite and reanalysis products, we examine this coupling during the lockdown in the Indo-Gangetic Basin, one of the world’s most populated and polluted regions. During the lockdown, the reduction (>10%) in columnar air pollution, expected to increase incoming solar radiation, was counteracted by a ~30% enhancement in cloud cover, causing little change in available energy at the surface. More importantly, the delay in winter crop harvesting increased surface vegetation cover, causing almost half the regional cooling (of -3.9 K) via evapotranspiration. Since this cooling was higher for rural areas, the daytime surface urban heat island (SUHI) intensity increased (by 0.20 to 0.41 K) during a period of reduced human activity. Our study provides strong observational evidence of the influence of agricultural activity on both urban and rural climate in this region.