Regarding petition in high court- chennai

You should file a police complaint first and simultaneously you can file for writ petition jointly seeking investigation through vigilance  department

A petition under Article 226 of the Constitution is filed in the cases concerning violation of fundamental rights or where there's an issue involving public interest. To address the situation you've described, a Public Interest Litigation (PIL) could be filed. It allows individuals or organizations to raise concerns on behalf of the public.

Regarding illegal land acquisition and cheating, the High Court can intervene, if it is found that there has been violation of fundamental rights or affects the public at large. The court may direct an inquiry, order the government to take possession of the illegally acquired land, or take necessary steps to aid the situation. However, it's crucial to have substantial evidence to support your claims while filing a PIL.

It is better to consult and engage a local prudent lawyer for professional advise and necessary proceeding.