The school's drinking water supply is salty, which has caused many students to develop kidney stones and require operations to remove them. While the school provides drinking water, the high salt content is affecting the health of the students. The parents of the affected students are often working abroad, leaving their children with grandparents. To address this problem, the students propose installing a reverse osmosis water purification system to remove the salt from the school's drinking water supply and prevent further health issues among the students.