Most people in "the IT industry" are not coders and do not need github, a code repository, or even the most basic understanding of coding in order to do their jobs. Install a satellite dish? You're an IT worker. Do customer service for a telecom? You're an IT worker. Swap out failing hard drives in a server farm? You're an IT worker.

The impact of github being down is large, but it isn't going to take out 7-10% of India's GDP.