Why are Indians trying to talk in English with each other?

There are two types of people.

In the first category, people conversate in english with other to be fluent and they usually try to learn something new from their conversation.

People in the second category want to speak english as much as they can as they love this wonderful language. Or they are very passionate to communicate in widely accepted language.

There are deep roots to this answer. We have been ruled by Britain for hundreds of years. When our ancestors used to speak English they got respect from them and it waas easier to communicate as well. Britain not only ruled us but more than half the world hence making it a widely used language.

Lets say a French person comes to our country and talks with you in your native language you will respect him/her right? 

That respect has gone too far and we as Indians have started respecting each other on basis of fluent English, which is wrong but it is how it is.

Indians speak multiple languages. As a country, India is very diverse. Hindi, Kannada, Tamil etc. Also have multiple dialects within themselves. English becomes a common ground for communication between these people. Not only can you communicate with each other, but also with other people globally. This means that the world of opportunities opens up to you because English is universally well accepted. So, in short, for the purpose of communicating freely and leveraging opportunities from across the globe, Indians are learning how to speak English

Indians are in general multilingual people. There could be various reasons for learning English. It could be due to the language itself. It attracts hears to want to learn English. Then , by learning English ,we can discover new culture, people and activities. You can travel and survive with English knowledge. You can educate yourself and come into contracts and contacts for trade and business development.