The link between air pollution and rainfall is an interesting question.

There is some controversy but the article attached here claim that in China it can seriously reduce rainfall.

https://www.nature.com/news/2007/070305/full/070305-11.html

Thanks for your response.

Please have a look at the following link.

http://www.pas.va/content/dam/accademia/pdf/sv108/sv108-rosenfeld.pdf

It seems that bioparticles (bioaerosols) can act as condensation nuclei and reduce rainfall.

See the attached paper

Article Pollen Rupture and Its Impact on Precipitation in Clean Cont...

yes air pollution gases/particles prevent condensation process and they surround the cloud to arrest condensation so it reduce rainfall