Short answer
South Mumbai cloth markets (Kalbadevi, Mangaldas, Mulji Jetha, Mohatta, Chakla) are closed on Sundays. Central Mumbai markets (Dadar, Hindmata, Wadala, Gandhi Market) are closed on Mondays, and Ulhasnagar is closed on Thursdays.
Unlike Surat and Ahmedabad where all markets close on Sunday, Mumbai's textile hubs have different weekly holidays by zone—which actually lets you plan a 7-day non-stop sourcing trip:
Tell us what you're looking for and we'll point you to the right market or supplier.