In India people celebrate New Years in different days of a year. But most of these festivals coincide with specific days either during Harvest festivals or in March-April belt, Holi or Diwali.
Here is an incomplete list of New Year Days celebrated across various Indian states.
Belt 1: Holi – Phalguna Pournami (15 days before Ugadi) – In M.P, Rajastan, Bihar, U.P, Chattisgarh, Jharkhand
Belt 2: Ugadi/GudiPadwa/SajibuNongmaPanba,Cheiraoba/Navreh/ Thapna/ Chaitti – celebrated on Chaitra Suddha Padyami – sometimes coincides with 1st day of Spring accross the world – Karnataka, AP, Telangana/Maharashtra, Goa/Manipur/Hindus of J&K/Marwari people of Rajasthan, Haryana, most of the people in H.P.
Cheti Chand – one day after Ugadi – Celebrated as New Year by Sindhis.
Interestingly, Neypi is the new year of Balanese people in Indonesia which falls on the same day as Ugadi.
Belt 3: Bihu/ Puthnadu/Vishu/Mahabishuba Sankranti/Vaisakhi/Jude-Sheetal/Poila Boishakh– April 14th, 15th - in Assam/ T.N/ Kerala/ Orissa/ Punjab, Haryana/ Maithili people in Nepal and India/ West Bengal and Bangladesh
All those states which have a culture of following Solar calendar (T.N, Kerala, West Bengal, Orissa, Assam, etc.), have their new year in Mid-April. The 3rd belt as shown above.
This calendar is followed in few other Asian countries hence this day also coincides with the traditional new year in Burma, Cambodia, Laos, Sri Lanka, Bangladesh, Nepal and Thailand.
All those whose follow lunisolar calendar, which majority of India follows, have new year as shown above in belt 1, belt 2, belt 4. But why does these dates differ?
This is because, though everybody following lunisolar calendar, it is either based on Vikrama samvatsaram (Bikram Samvat) started by king Vikramaditya or the Shaka samwat started by king Shalivahana so the day they regard as first day is different.
Saka Samvat and Vikram Samvat are two commonly used calendars in India. Saka Samvat has been adopted as an official civil calendar by India. Saka Samvat starts from 78 AD, whereas Vikram Samvat starts from 57 BC.
The first two belts of people follow the Sakha calendar.
For the people who celebrate Holi as first day, the end of month is after the full moon day (Pournami) instead of New moon day (Amavasya). Hence the 15 day gap between the New Years.
For the 2nd belt of people, the month ends with an Amavasya, and that is the reason why many people across India celebrate the Chaitra suddha Padyami as the New Year.
One exception is the Gujaratis, who follow Vikrama samvatsaram. According to the 2nd belt of people the month of Karthika or the day after Diwali is the middle day of the year i.e 6 months have already passed. But some cultures like the Gujaratis have this day as the first day and the Chaitra month as the middle month.
Hence. only Gujaratis celebrate Diwali as New Year. Most others either celebrate on Holi or Ugadi.