Industrial Location can be influenced by a variety of factors.
Of course, it is very rare to find all these factors in one place. Therefore, these industries tend to be located at the most appropriate place where all the factors are either available or can be arranged at a low cost.
Sometimes, industries are located in or near cities. Thus, industrialization and urbanization go hand in hand.
After an industrial activity starts, urbanization follows. This is because, cities provide markets and services such as banking, insurance, transport, labor, consultants and financial advice, etc. to the industry.
When many industries tend to come together to make use of the advantages offered by the urban centers known as agglomeration economies.
For example - IT setups tend to cluster in similar regions, such as Silicon Valley California, and major cities, like London. The reason is that these areas attract highly skilled IT personnel and it is easier to recruit the right staff.
In the pre-independence period, most manufacturing units were located in places from the point of view of overseas trade such as Mumbai, Kolkata, Chennai, etc.