Carissa salicina

About

Carissa carandas is a species of flowering shrub in the family Apocynaceae. It produces berry-sized fruits that are commonly used as a condiment in Indian pickles and spices. The fruit is black and tastes sweet or sour depending on the plant. It is a hardy, drought-tolerant plant that thrives well in a wide range of soils. Common names in English include Bengal currant, Carandas plum and karanda.

Summary from Wikipedia