Explanation:

- Onam: Primarily celebrated in Kerala, Onam is a major Hindu festival. It's associated with the harvest season and does not mark the start of the Telugu New Year.

- Gudi Padwa: This festival marks the beginning of the New Year in Maharashtra. It's similar in timing and cultural significance to Ugadi but is not related to the Telugu New Year.

- Pongal: Celebrated mainly in Tamil Nadu, Pongal is a harvest festival. It is not linked to the start of the Telugu New Year.

- Ugadi: Ugadi is indeed the festival that marks the commencement of the Telugu New Year. Celebrated with great enthusiasm, it signifies a fresh start for the Telugu-speaking communities.