The correct answer is 1, 2 and 3. The National Action Plan on Climate Change (NAPCC) has identified these key areas related to the National Water Mission studies on the management of surface water resources, management and regulation of groundwater resources, upgrading storage structures for fresh and drainage system for wastewater, conservation of wetland, and development of desalination technologies etc. required to be considered while preparing the comprehensive document for the National Water Mission. Additional Information The National Action Plan on Climate Change (NAPCC) describes the features of the National Water Mission as under: “A National Water Mission will be mounted to ensure integrated water resource management helping to conserve water, minimize wastage and ensure more equitable distribution both across and within states. The Mission will take into account the provisions of the National Water Policy and develop a framework to optimize water use by increasing water use efficiency by 20% through regulatory mechanisms with differential entitlements and pricing. It will seek to ensure that a considerable share of the water needs of urban areas are met through recycling of wastewater, and ensuring that the water requirements of coastal cities with inadequate alternative sources of water are met through the adoption of new and appropriate technologies such as low-temperature desalination technologies that allow for the use of ocean water. The National Water Policy would be revisited in consultation with the States to ensure basin-level management strategies to deal with variability in rainfall and river flows due to climate change.