I found Ambat chukka on my last visit to the market. It is a tangy cousin of Palak(Appearance isl ike Palak but is very sour to taste.) In fact I googled to find out what it is called in other languages and was surprised to know that in Hindi it is actually called Khatti Palak. In English it is Green Sorrel and for other Indian languages see this page here
Ambat Chukka with hot plain rice is one of the best comfort foods for me.