Avial is a popular South Indian dish that originated in the state of Kerala. It is a vegetable stew made with a variety of locally available vegetables and coconut-based gravy. Over time, Avial has become famous not just in Kerala but all over India and the world.

Reasons for Avial's popularity:

1. Unique taste: Avial has a distinct taste that comes from the blend of various vegetables and coconut-based gravy. The dish has a mild and refreshing flavour that is loved by many.

2. Healthy: Avial is a healthy dish as it is made with a variety of vegetables that are rich in nutrients. It is also a vegan and gluten-free dish.

3. Versatile: Avial can be served as a side dish with rice or roti, or as a main course. It is also a popular dish during festivals and special occasions.

4. Regional popularity: Avial is a popular dish in Kerala, but it has also gained popularity in other South Indian states such as Tamil Nadu and Karnataka.

5. Celebrity endorsements: Many famous chefs and food bloggers have endorsed Avial, which has helped in spreading its popularity.

In conclusion, Avial is a delicious and healthy dish that has become famous all over India and the world due to its unique taste, versatility, and regional popularity.