I will be arriving at Frankfurt airport terminal 1 at 18:00 from New Delhi and I have a domestic flight to Munich at 19:15 from the same terminal. Would it be manageable?
Yes since its at the same terminal ..
Is this on one ticket with Lufthansa or a code share partner? Should be a legal connection. If you are late landing and miss it, it is the last flight of the day. They will put you on a flight next day and depending on the circumstances, may get you a free hotel for the night and food vouchers.
In Europe its the law if you airlines keep you waiting 3 hours or more they have to give give you a hotel and refund your ticket . My husband was stuck in London for 1 1/2 days flying home the the usa and they refunded him 600 Euros plus gave him a hotel food etc. But you should be fine I fly there all the time as long as you don't have to switch terminals
It's a code share with Air India.
They will put you on a flight next day and depending on the circumstances, may get you a free hotel for the night and food vouchers.
They will give you a train ticket, provided you can catch one of the four trains departing between 19:36 and 20:53.