For decades, we have been looking for Dark Matter in the form of WIMPs, but many other possibilities exist. Light DM, intended as having a mass between 1 MeV and about 1 GeV, is one of these possibilities, which is interesting both theoretically and phenomenologically. Testing it via Indirect Detection is more challenging than WIMPs, but X-ray measurements provide a very powerful handle. They currently impose stringent constraints, and allow in perspective to explore further this relatively new region of the parameter space.