Rocket engines are actually easier to develop than aerospace engines because they are one-time used.
Maybe their first step is to stop the brain drain. I notice that there‘s a lot of Indians who are genuinely passionate about engineering here in the EU as opposed to say Indonesia where young people gravitate towards finance and „easy jobs“. India should focus on building at least one liveable city so that people can feel like staying and a lot of problems would sort themselves out. Even their $10,000 GDP per capita cities look straight out of 5th world but this is another topic.