Heat the ghee or vegetable oil in a large pot over medium heat.

Add the cumin seeds and cook until they start to sizzle.

Add the chopped onion, minced garlic, and chopped green chili pepper to the pot and cook until the onion becomes translucent.

Add the diced tomatoes, turmeric powder, red chili powder, garam masala, sugar, and salt to the pot. Cook for 5 minutes, stirring occasionally.

Pour in the vegetable broth and bring the soup to a boil.

Reduce the heat and let the soup simmer for 20 minutes.

Remove the pot from the heat and let the soup cool slightly.

Use an immersion blender or a regular blender to puree the soup until smooth.

Return the soup to the pot and reheat over low heat.

Serve the Indian tomato soup hot, garnished with fresh cilantro leaves.