It's a longhorn beetle (Cerambycidae).
Most likely, it's a Red-spotted longhorn beetle (Batocera rufomaculata), also known as a mango tree borer, mango stem-borer and tropical fig borer.
See this SE question pertaining to the same insect.
Country check-list: China, India, Israel, Jordan, Laos, Lebanon, Madagascar, Malaysia, Mauritius, Myanmar, Pakistan, Puerto Rico, Sri Lanka, Syria, Thailand, Virgin Islands [Might Not be complete]
Food: Ficus carica L. (Fig), Carica papaya L. (Papaya), Mangifera indica L. (Mango), Shorea robusta Gaertner f. (Sal Tree)
It might also be B. parryi, which, similar to B. rufomaculata, is common in SE Asia (but which is absent from Western Asia or Africa where B. rufomaculata is also found). Since you live in India, both are possible. I will look for a key to determine how to differentiate the 2 species.
Meanwhile, here is a list of related species in the Lamiinae subfamily for further reference.
Also, a great resource (including keys) for wood boring beetles of the world!