Each country has their own rules regarding layovers for citizens of India.
U.S requires a transit visa for Indian citizens. The wait for a visa interview can be a 2-3 months.
You need to check your planned routing and see the regulations of each country you are landing in. The rules vary from country to country.
I will give my itinerary as an example.
I am going from Chennai to Delhi. Then I will catch a flight to Toronto via Munich.
German law allows Indians to travel without a transit visa provided that you have a valid visa of a few countries. Canada is one of those countries, so I can transit in Munich airport without a transit visa since I would have a Canadian TRV.
However, you cannot have a layover in another airport that is part of the schengen area, as you would be flying a "domestic flight". If you want to do that, then you will have to apply for a transit visa.
As you can see it is complicated and depends on your route.