Explanation:

 Haldia is a centre for many petrochemical businesses, and is being developed as a major trade port for Kolkata. It is an industrial city and municipality in Purba Medinipur district, in the Indian state of West Bengal.Petrochemicals are chemical products derived from petroleum. Some chemical compounds made from petroleum are also obtained from other fossil fuels, such as coal or natural gas, or renewable sources such as corn, palm fruit or sugar cane. The two most common petrochemical classes are olefins and aromatics.