Dharavi is the largest slum in Asia. It is situated near Bandra in Mumbai, the economic capital of India. Mumbai was once upon a group of disjointed islands and one had to take the boat to reach an island from another.
British got the island in dowry from Portuguese and saw its strategic importance chose to develop the place because it has the finest natural harbor in the world.
They encouraged the Parsees to come and open industries and develop the city. Soon the city began to expand and people flocked to it in search of better future.
The islands were abridged by reclaiming the land from the sea and continuity was achieved. The city as such has no chance of expanding in all directions like Delhi because of its shape and detached location from the rest of India.
It soon became over crowded. Those who work for creation of wealth for this city, found it difficult to find a place to live in. The slums sprouted everywhere which have very cramped places to live in. Hygiene is virtually non existent. But even then millions live here.
One such area is Dharavi. It has been depicted in many movies like Salaam Bombay by Mira Nair and Slumdog Millionaire by Danny Boyle. The area consists of labyrinth of very narrow lanes. I think one can get lost and never come out. Economically, the people work here to collect the waste materials and recycle them.
One such material is recycling of Aluminum which is found in the form of cans of beverages. Unknowingly these people are shielding the city from the pollution that this metal can do.
Aluminum is very difficult to obtain from its ore because of the lengthy processes like dissolving it in alkali solution, then precipitating it in the form of Alumina and then carrying out electricity consuming process of electrolysis to obtain the pure metal.
The process here is to dip the cans in mild acid to remove the coverings and then after washing and drying melt the individual mass of cans into one solid ingot in a hearth which is a hole in the earth where coals are burnt with the help of air conveyed through a pipe.
The cans are put on a silicon carbide crucible. This way the metal is melted and is ready to use in making utensils and other articles. These people work for hours to earn a living.