Vapi is a city and a municipality in Valsad district in the Indian state of Gujarat. It is situated on the banks of Damanganga River in southern Gujarat, India. Vapi falls under the taluka administration of Pardi.

Around 28 km south of the district headquarter city of Valsad, it is surrounded by Union Territories of Daman on the west and by Dadra and Nagar Haveli on the east. Economic and industrial growth of the recent decades has, however, blurred the physical boundaries, and the small stretch of roughly 21 km of Daman-Vapi-Silvassa has almost become a monolith.

The industrial township of Vapi holds its place of importance on the "industrial" map and it is the largest industrial area in Asia in terms of small-scale industries, dominated by chemical industry plants, along with their unfortunate hazards.

It also has the dubious distinction of being on the list of the 10 Worst polluted places in the world.

National Highway 8 bisects the town, creating east and west parts - the western part being the original old town-place, and the eastern part mainly hosting the industries and the newly constructed residential areas. Via the modernized highway, Mumbai is about 180 km to the south and the city of Surat is about 125 km to the north.

To cater to the industry, the town handles a huge amount of what is called a "floating population" and the Vapi railway station on the Mumbai-Vapirail link of Western Railway (India) has become the direct beneficiary in terms of revenues due to daily commuters.

The Arabian Sea is about 7 km to the west, where the Daman Ganga River creates its delta. The city has tropical weather and enjoys three distinct seasons of mild winter, moderate summer and heavy monsoon, with rainfall ranging from 100 inches to 120 inches per annum. In addition to the old town, some of the other main residential areas and suburbs are Gunjan, Chanod Colony, Vapi Town, Hariya Park, Chala and also up coming Balitha n Salvav with many other small areas.

Proximity to the larger cities of Mumbai and Surat, coupled with liberal Government policy, has helped Vapi and surrounding areas in attaining their current level of industrial growth. The "Vapi Industrial Estate" was started by GIDC in 1967, and has spread to 11.4 km² and houses over 1500 industries, the majority of which are small-scale units (SSIs).

Today, about 70% of the total industries in the township are chemical plants, mainly for chemical distillation and the production of pesticides, dyes, dye intermediaries and paints. Other major industries include paper, packaging, pharmaceuticals, plastics, rubber, textiles, wood, glass, and food products. Another striking feature of Vapi is the Comman Effluent Treatment Plant . This is the largest of its kind in Asia, treating the pollutants from these industries before the effluent is released in the Daman Ganga River. The CETP is run by Vapi Waste & Effluent Management Company, promoted by the Vapi Industries Association.