Starlight provides a powerful probe of planetary atmospheres across a wide range of environments. Starlight passing through a planetary atmosphere carries rich information about its structure, composition, and evolution. In the Solar System, stellar occultations have emerged as a precise and powerful technique to probe tenuous atmospheres and rings. In this talk, I will discuss recent results on the atmospheres of Pluto and Triton, derived from observations with the Devasthal Optical Telescope and the Himalayan Chandra Telescope using two of TIFR's instruments - TIRCAM2 and u-TIRSPEC.
Beyond the Solar System, the discovery of over 6,000 exoplanets has shifted the focus from detection to atmospheric characterization. In the second part of the talk, I will present an overview of ExoWorlds, a proposed space mission of ISRO designed to characterize exoplanetary atmospheres.