I didn't go into it in my original comment because I'm not an expert on the economics of on-site generation either. However, fuel availability — and materials availability in general — is definitely difficult because of India's other major problem: a lock of good ground transportation and infrastructure.

The roads are narrow and dangerous, which also means that they are unreliable and slow. For example, it can routinely take 3-4 hours to travel just 60 miles, in a passenger vehicle. The issues only get worse if you need to move a large amount of materials or goods.

Many commercial and residential complexes in India do have a backup power source, but I don't think it would be feasible to run a factory off that.