Question

One of the most densely populated regions of the world in India is

Answer 1

The answer of you question is "Mumbai"
It is considered one of the most populated region in the world based on the  number of inhabitant living  per square kilometer. It has the population exceeding the 21 million who are living in the area of about 603 km2 approximately ( Total Mumbai  area). It is also considered one of the larges city of the country of India .

Interestingly, Mumbai is also considered the wealthiest and richest city of India because of the number of richest people living in the area. 

Answer 2

India is composed of union of 29 states and 7 union domains. Starting year 2011, with an expected populace of 1.2 billion, India is the world's second most crowded nation after the People's Republic of China on the planet. India involves 2.4 percent of the zone and is home to 17.5 percent of the populace. After the Gangetic fields, the eastern and western beach front areas of the Deccan level are the most thickly populated locales of India. The Thar Desert in western Rajasthan is a standout amongst the most thickly populated betrays on the planet. The northern and north-eastern states along the Himalayas contain chilly bone-dry deserts with rich valleys. These states have less populace thickness because of unyielding physical hindrances.