Soak the chickpeas overnight.
Drain and pressure cook them with four cups of water.
Tie a tbsp of tea leaves and gooseberry in a muslin cloth.
Add this bag and salt to the chickpeas and pressure cook for 6-8 whistles, or till the chickpeas are completely soft and cooked.
Drain the chickpeas , reserve the water.
Discard the muslin cloth.
Add oil to the pan and saute onions and green chillies. Saute till onion is pink.
Add channa masala and saute for another few minutes.
Add the tomato purée and cook till dry.
Add the chickpeas and the reserved water from them.
Simmer and cook for 5-7 minutes, the channa should be semi solid.