India is known for its overpopulated locations. if you take a look at its bustling cities, crowded markets and jammed roads, you will have no doubts about its dense population.
I think the reasons can be found in the attitude of their society. As far as I know, Indian people are outgoing, open-minded people who often organise gatherings among friends and relatives. This kind of attitude could contribute to a denser population as families are big and they want to keep this tradition. Yes, I think the keeping of lineage of their families is an important factor in this question.
However, there might be another reason for this phenomenon. I think poverty also contributes to overpopulation as people do not have enough money to spend on condoms and they are too poor to take any preventative measures. Also, a great number of them are simply not informed and they do not know about the consequences of overpopulation. Little money is spent on lectures, public information and people are not warned about the long-term effects.
As you see, it is difficult to do anything about their mentality but better economy could raise awareness and reduce the problem of overpopulation there.