PRAYAGRAJ, March 24 -- A former professor of department of botany, Allahabad University, prof NB Singh has devoted his life to saving the house sparrow (passerby domesticus) from perishing, due to its declining population.

Singh has been riding a cycle for over a decade to save on the fuel and meet the expenses to save the bird from perishing. Known as 'Hariyali Guru', a name given by his students in view of his passion for saving the environment, the 68-year-old has distributed over 1.50 lakh wooden sparrow houses to people in both Prayagraj as well as his native village Bikna in Sultanpur district.

"I get sparrow houses made of plywood. Each cost Rs.250. In my village, a time came that there were no sparrows. But after a decade I can ...