Daurala near Meerut restored its polluted groundwater using which universal principle?

1. Daurala's groundwater had heavy metals from untreated industrial waste. 2. An NGO and industry applied the polluter pays law. 3. Ponds were desilted and 1000 trees planted. _Source: syllabus Geography, India People and Economy, Chapter 12, Geographical Perspective on Selected Issues and Problems._