• Brainly User
London is better because
1-Low Population Density
⇒Population density of London is 5206 people/km² but Population density of Mumbai is much more than London that is 20694 people/km²   
2-Public Health Care
⇒There is public health care in London but there is not any public health care in Mumbai.
3-Is a capital city
⇒London is a capital city of Great Britain but Mumbai is not.
4-Better Transport system
⇒London has better Roadways,Seaways and Airways as compared to Mumbai.
5-Underdevelopment stage
⇒Mumbai is developing city whereas London is a fully developed city.

Mumbai is better because
1-Site of pilgrimages
⇒Mumbai has much more pilgrimages as compared to London.
2-Average maximum temperature
⇒Mumbai has average temperature of about 31.7°C and London have just 15.2°C.
3-Has a beach
⇒Mumbai has a beach but London has not any beach
4-Has lake
⇒Mumbai has number of lakes but London has not.
5-Low vat rate 
⇒Mumbai has low vat rate i.e 12.5% but London has 20% vat rate.