Vertical farming is a greenhouse method of agriculture where commercially viable crops are cultivated inside multi-storey buildings in cities to imitate natural ecological systems. Since everything is 'hydroponic' in this practice, i.e., in mineral nutrient solutions, the problems of soil erosion , pesticide toxicity are not there. Vertical farming is also a proposal to build high rise buildings within urban areas to enable the growing of food crops to help avoid the impending food shortage which is envisaged in the near future.
Basically, it is like a high rise greenhouse, sometimes having the label 'farmscrapers'.
In India, commercial vertical farming is not yet established but yes, vertical gardening/Living walls has already been erected successfully by us. This works on the same concept of hydroponics.