How it works

China's common catalysts used for cloud seeding in precipitation enhancement include silver iodide, dry ice and liquid nitrogen.

Silver iodide works more efficiently when seeded into clouds that have a temperature between -6 and -18 C, while dry ice and liquid nitrogen work more efficiently when seeded into clouds with a temperature between -1 and -6 C.

Clouds are divided into cold clouds and warm clouds. Cold clouds refer to those below 0 C while warm ones refer to those above 0 C.