Workers belong to Brihanmumbai Electric Supply and Transport undertaking, which runs Mumbai’s bus service, began an indefinite strike on Monday, protesting against salary delays. At least 3,700 BEST buses ply in the city, catering to about 29 lakh commuters every day, the Hindustan Times reported.

The BEST Sanyukta Kamgar Kriti Samiti, an umbrella organisation to which all of BEST’s unions belong, refused to back down from its strike call despite holding talks with civic chief Ashok Mehta and leaders of the ruling Shiv Sena. At least 36,000 workers are part of the Samiti, including unions backed by the Sena and its ally, the Bharatiya Janata Party. The workers said they had not been paid in three months.

The BEST administration warned employees of action in a notice sent out late on Sunday, The Times of India reported, but its General Manager Surendrakumar Bagde said they had agreed to pay salaries by the 10th of every month. However, union leader Sharad Rao said the workers would not call off the strike unless this promise was made in writing.

The demand for buses is especially high on Raksha Bandhan, which will be observed on Monday.