In the 1600’s villagers of the Thar Desert evolved an ingenious system of rainwater harvesting known as kunds or kundis. They are simply an impermeable catchment area of about 2,000 square meters that drains into a covered underground tank. The tank is about 2m wide and 6m deep. Originally the impermeable catchment area was created from clay, however concrete is now commonly used. To reduce costs, a soil binding polymer is now been investigated.