Chop the zucchini and chayote into cubes. Pressure cook the dhal along with garlic, tomatoes,hing and chayote /chow chow for 3 whistles. Slit the green chilly.
Add the tamarind paste to the dhal mixture once it's cooked. Give it a boil. Now add the zucchini ,turmeric powder,red chilli powder and cook for 5 more minutes.
At the same time, heat the tadka pan and add the oil. Add the mustard seeds and it will sizzle if the oil is hot.
Divide the red chilly into pieces. Add this after u've added the mustard seeds. Followed by Curry leaves.
Pour this mixture into the boiling dhal and combine well. Switch off. Garnish with corainder leaves and serve.