Wikipedia
Chaiti
Chaiti are a semi-classical songs sung in the Hindu calendar month of Chait. These songs are rendered during the Holy month of Sri Rama Navami in March/April. It falls under light classical form of Hindustani classical music. The songs typically has the name of Lord Rama.
It comes in the series of season songs, like Kajari, Hori and Sawani, and is traditionally sung in the villages and towns of Uttar Pradesh: around Banaras, Mirzapur, Mathura, Allahabad and the Bhojpur regions of Bihar. Some of the popular singers of Chaiti are Girija Devi etc.