Another factor of the Indian national government's failure with COVID vaccines was simply not sending any significant amounts of money to the companies that were either manufacturing them under contract like the Serum Institute of India (SII, largest in the world by doses, 1.5 billion/year in 2020). After that second wave, as far as I know the first really big wave hit, the CEO of the SII had to flee the country because of threatening demands he was getting from various powerful figures in various part of the country.

Although the SII also suffered from supply chain issues like everyone else, such as a world wide shortage of 2,000 L sterile plastic bags in which to culture cells and probably bacteria like the E. Coli used in the first step of making the mRNA vaccines.