firstly, in a mixi jar take 1 cup coriander, ½ cup mint, 1 inch ginger, 1 chilli.
add ¼ cup water and blend to smooth paste.
transfer the green chutney into a large bowl.
add 1 cup tamarind extract. i have soaked a ball sized tamarind in water for 30 minutes, and squeezed out the juice.
also add 1 tsp chaat masala, ½ tsp cumin powder, ½ tsp chilli powder, 1 tsp aamchur, pinch hing and 1 tsp salt.
mix well making sure all the spices are well combined.
further, add 5 cup cold water and mix well adjusting the spices as required.
now add 2 tbsp coriander, 2 tbsp mint, half lemon and half onion.
mix well and refrigerate to keep the pani chilled.