Peak electrical demand does not coincide with solar generation. Generally, peak demand is either early in the morning or the late afternoon, when solar production tapers. In order to make up the difference, you'd need a couple thousand megawatt-hours of battery capacity for most regions. You'd also need this to happen twice a day - either side of typical working hours.

This is true in Tokyo and Mumbai. Tokyo's data is here https://www.tepco.co.jp/en/forecast/html/calendar-e.html

Mumbai's peak electricity demand is typically in the late afternoon, when solar output starts to dip.

The solution to this is not more battery capacity, but varied power sources. Wind, solar, gas, nuclear, etc.