In Jainism, "Chovihar" (or Chauvihar) refers to the practice of not consuming any food or water after sunset until sunrise the next day. The exact time for Chovihar begins at sunset (Sandhya) each day, and this time changes daily according to the local sunset time.

For Mumbai, you should observe Chovihar from the time of sunset today. You can refer to a Jain Panchang or a reliable local sunset calendar for Mumbai to know the precise sunset time for today. After this time, Jains traditionally refrain from eating or drinking until the next day's sunrise.

If you need the exact sunset time, please consult your local Jain temple or Jain Panchang, as they often provide daily Chovihar timings specific to your city.