samantha - India Peravurani Tamil Nadu

During my childhood days I used to watch many house sparrows chirping,hopping, flying and living around happily.But now a days I could hardly see house sparrows, I spent one year (2011) in Leuven, Belgium, there i could see many house sparrows. It is very sad to digest house sparrows are disappearing in our nativity.we need to know what are the reasons for this and how can we promote the livelihood of house sparrows.