This study aims to investigate the direct shortwave (SW) radiative forcing (RF) and heating rates of the Asian Tropopause Aerosol Layer (ATAL) in the upper troposphere–lower stratosphere (UTLS) using in situ observations from the Balloon measurement campaigns of the Asian Tropopause Aerosol Layer (BATAL) conducted between 2014 and 2018. Measurements were obtained over three distinct locations in India: Gadanki (13.48° N, 79.18° E), Hyderabad (17.47° N, 78.58° E), and Varanasi (25.27° N, 82.99° E). Given the ambiguity in the chemical composition of ATAL from several reported studies, seven different aerosol mixtures – comprising sulfate (SUL), nitrate (NIT), organic carbon (OC), and ammonium (AM) – were considered to assess their impact on estimates of ATAL radiative forcing and heating rates. A pronounced enhancement in aerosol backscatter was observed at ATAL altitudes (13 to 19 km) across all locations, with the backscatter ratio (BSR; at 455 nm) peaking at 1.07 over Varanasi and Hyderabad, followed by 1.06 over Gadanki. Radiative forcing estimates indicate a net warming effect, with ATAL contributing up to 3 % of the total columnar atmospheric forcing. Heating rates reveal a marked increase in aerosol-induced warming at ATAL altitudes, with maximum heating rates reaching 0.03 K d−1 across the study locations. The radiative impact of ATAL aerosols is highly sensitive to variations in the aerosol composition. Compared to a reference case with a stratospheric sulfate background, the ATAL radiative forcing varies between 0.03 and 0.28 W m−2 (1.5- to 14-fold increase). At the same time, heating rates exhibit a 30-fold increase, reaching 0.03 K d−1, depending on the aerosol mixture. Despite these strong localized effects within the UTLS, the overall contribution to total columnar aerosol forcing remains moderate (up to 5 %), underscoring the importance of aerosol composition in determining ATAL's radiative influence.