You can transit UK/France/Germany to arrive in India. Depending on your passport and your port of arrival after transiting, countries/places visited in the last couple of weeks, temp readings at various places etc. etc. you may be required to quarantine anywhere during your travel in USA or India or somewhere in-between.
The situation is very complicated right now so you're dependent on US travel rules, India travel rules & if applicable the transit countries travel rules (which can affect you transiting or reaching your destination or home). Also these rules are constantly changing in your home, destination & transit countries.
I would strongly you advise you to book direct at least between USA & IND - that would probably give you the best odds of making the trip. Also, given how stressful flying now is, it would also give you the least amount of stress/hassle though it might not be the cheapest. Make sure the airlines you choose has a good cancellation policy. I'd probably pick LAX-SFO (UA) - DEL (UA) - BOM (UK).
Your best guide once you've picked your route/airline would be the airlines' website. That would give you the most up-to-date information about travel restrictions etc. Again - those rules might not hold true on your date of journey.
For general guides you can refer to these:
1. TIMATIC through here or elsewhere -
https://www.united.com/web/en-US/app...aspx?i=TIMATIC
2.
https://www.united.com/ual/en/in/fly...l/notices.html
3.
https://travel.state.gov/content/tra...formation.html
4.
https://boi.gov.in/content/advisory-...ted-covid-19-0