Football popularity in India can be broken in 2-3 different groups. First, the traditional football strongholds in India: Kerala/West Bengal/Goa and North East. These regions have been the bedrock of Indian football since a long time and Football World Cup is a big deal there. Normally, you would find a lot of Brazil/Argentina fans in these regions. Also, a lot of Indians in Qatar/Middle East are from the Indian state of Kerala which is crazy about football.
Second and newer group of football fanatics are the EPL/Champions League watchers in urban areas. I don't have numbers but viewership of EPL in India is quite high. And, in the recent past, I have seen that not only is this new generation consuming football and part of the online fan groups of various clubs, but is also contributing to fan driven data/tactic analysis. And in recent past with ease of following other leagues as well, other European leagues are also getting a foothold in India.
And third group would be the followers of Indian football, outside the traditional regions in group 1. Those who follow Indian team and ISL.
First 2 groups are excited about the World Cup. But, it is the usual excitement and not insane hype. There is not much media coverage or ad campaigns regarding WC. Normal Indian sports fan is more excited about the India-NZ T20 series but there is still a significant group which is excited about Football World Cup. And obviously, those who are residing in Qatar or other Gulf states, are really excited about the World Cup as for them it is almost like a home World Cup.