S1: The ecosystem of water is complex and many environmental factors are intricately linked. P: Thick forests make for excellent catchments. Q: The problems we see are because we have undermined these links over decades. R: First, rain and snowfall are the only sources of water – about 99%. S: In the four months of monsoon, there are about 30-35 downpours and the challenge is to hold this water in systems that can last us over 365 days. S6: The trees slowly transfer rainwater into the sub-soil and this is critical for sustaining water for months after the rains. Find the correct sequence of P, Q, R and S.