Soak the whole jowar overnight in enough water. Next day, drain all the water.
Combine soaked and drained jowar, 1 cup of water and salt in a pressure cooker, mix well and pressure cook for 5 whistles.
Allow the steam to escape before opening the lid. Keep the cooked whole jowar aside without draining the water.
Heat the oil in a broad non-stick pan and add the cumin seeds.
When the seeds crackle, add the asafoetida, green chillies, red, green, yellow capsicum and the zucchini and sauté on a medium flame for 1 to 2 minutes.
Add a little salt, cooked jowar (along with the water), mix well and cook on a medium flame for 3 to 4 minutes or till the water dries up, while stirring occasionally.
Add the milk, mix well and cook on a medium flame for 2 to 3 minutes, while stirring occasionally.
Add the coriander, mix well and cook on a medium flame for 2 minutes, while stirring occasionally.