Okay kiddo, so Parsi theatre is a kind of theatre that was really popular in India a long time ago. People from the Parsi community in India, who practiced the Zoroastrian religion, started putting on plays in the late 1800s. These plays were usually funny and had lots of singing and dancing, and were performed on big stages with lots of colorful costumes and decorations.
The plays were written in a mix of Hindi, Urdu, and Gujarati, which were the main languages spoken by the Parsi community. And because the plays were so popular, they started to attract audiences from different communities and religions, not just Parsis.
One of the most famous Parsi theatre companies was called the Parsi Natak Mandali, and they performed all over India and even in other parts of the world. The actors were really talented, and some of them became household names.
But over time, Parsi theatre started to lose its popularity as new forms of entertainment, like movies and TV shows, became more popular. Nowadays, you don't see many Parsi plays being performed, but the ones that do still happen are really special and help keep this important part of Indian cultural history alive.