Pickling is an ancient gastronomic craft of preserving food in brine and/or vinegar. 
Multiple ancient civilizations, such as ancient Egyptians, Chinese, and Indians, used pickling for food preservation

Pickles are a very important part of the Indian cuisine.

Pickles are good appetizers, consumed by people of all ages and contain large amounts of lactobacilli which are important for the digestion of grains and vegetables, and have beneficial probiotic properties. Probiotics are live bacteria and yeasts that are good for you, especially your digestive system. 

Lactobacillus exhibits a mutualistic relationship with the human body, as it protects the host against potential invasions by pathogens, and in turn, the host provides a source of nutrients; it is diverse in its application to maintain human well-being, as it can help treat diarrhea, vaginal infections, and skin disorders such as eczema.

(Sources of Information: en.m.wikipedia.org, ncbi.nlm.nih.gov & sciencedirect.com)