Black Carbon-Climate Interactions Regulate Dust Burdens over India Revealed during COVID-19

India as a hotspot for air pollution has heavy black carbon (BC) and dust (DU) loadings. BC has been identified to significantly impact the Indian climate. However, whether BC-climate interactions regulate Indian DU during the premonsoon season is unclear. Here, using long-term Reanalysis data and global model simulations, we show that northern Indian DU is positively correlated to northern Indian BC while negatively correlated to southern Indian BC. We further identify the mechanism of BC-dust-climate interactions revealed during COVID-19. BC reduction in northern India due to lockdown decreases solar heating in the atmosphere and increases surface albedo of the Tibetan Plateau (TP), inducing a descending motion in the mid- and lower troposphere. Colder and heavier air from the TP in northern India together with warmer and moister southern Indian air heated by BC from enhanced crop residue burning results in easterly wind anomalies, which reduces dust transport from the Middle East and Sahara and local dust emissions from the Thar Desert. The BC-dust-climate interactions during the premonsoon season delay the outbreak of the subsequent Indian summer monsoon.