Mumbai (India) is 1370 times as big as Vatican City
Mumbai, formerly known as Bombay, the official name until 1995) is the capital city of the Indian state of Maharashtra. According to the United Nations, as of 2018, Mumbai is the second-most populous city in the country after Delhi and the seventh-most populous city in the world with a population of roughly 20 million.
Vatican City, officially the Vatican City State, is the Holy See's independent city state, an enclave within Rome, Italy. The Vatican City State, also known as The Vatican, became independent from Italy with the Lateran Treaty (1929). With an area of 49 (121 acres) and a population of about 825, it is the smallest sovereign state in the world by both area and population.