Mumbai, India. Trains in Mumbai are usually overcrowded, especially during peak hours. Mumbai is one of the largest cities in the world with around 20 million inhabitants. The city is a magnet for migrants from various parts of India, leading to a huge increase in population and demand for transport. Although the local train network has been operating since colonial times, infrastructure is inadequate to keep pace with population growth. About 7,5 million people use the trains every day, while the capacity of the trains is not sufficient.