in Sanskrit, Kannada, Tamil and Telugu, Chavath ( चवथ ) in Konkani and as Chathaa (चथा) in Nepal Bhasa. It is celebrated as it is the birthday of Lord Ganesha. The festival is observed in the Hindu calendar month of Bhaadrapada, starting on the shukla chaturthi (fourth day of the waxing moon period). Typically, the day falls sometime between 20 August and 15 September. The festival lasts for 10 days, ending on Ananta Chaturdashi. This festival is observed in the lunar month of bhadrapada shukla paksha chathurthi madhyahana vyapini purvaviddha. if chaturthi prevails on both days, the first day should be taken. Even if chaturthi prevails for complete duration of madhyahana on the second day, but if it prevails on previous day's madhyahana period even for one ghatika (24 minutes) the previous day should be taken. (Ref. Dharmasindhu and Indian Calendric System, by Commodore S.K. Chatterjee (Retd). Madhyahana is the 3rd / 5th part of the day (Sunrise-sunset).
Ganesha, the elephant-headed son of Shiva and Parvati, is widely worshipped as the supreme god of wisdom, prosperity and good fortune.
While celebrated all over India, it is most elaborate in Maharashtra, Goa (Biggest festival for Konkani people all over the world) Gujarat, Karnataka and Andhra Pradesh, and other areas which were former states of the Maratha Empire. Outside India, it is celebrated by Newars in Nepal and Tamil Hindus in Sri Lanka.