New Delhi, July 1 -- The Union environment ministry is facing a challenge, but of garden variety: bird droppings soiling the courtyard of Indira Paryavaran Bhawan, which houses it, and is among India's highest green-rated buildings. On Wednesday, the ministry invited proposals for solutions to the recurring problem of droppings in the central courtyard of the building and announced a reward of Rs.1 lakh for individuals or organisations with the best solution....