Full moon days in Hindu calendar are known as Purnima or Pournami.
South Indian people called it as Pournami, where as North Indians called it as Purnima.
Apart from festivals, Pournami is a very important and auspicious day in Hindu calendar. Pournami that falls in the month of Phalgun is called as Phalguna Purnima or Phalguna Pournami.
As per Hindu calendar, Phalguna Purnima is the last Purnima in the year.
One of the most popular festival Holi(festival of colors) is celebrated on Phalguna Purnima.
Phalguna Purnima is also known as Vasantha Purnima, as it coincides with Vasantha Ruthuvu(Rutu) and the day also coincides with Lakshmi Jayanthi (birth anniversary of Goddess Lakshmi).
In Andhra Pradesh, Karnataka, Tamilnadu, Telangana (South Indian States), the day is observed as Kama Dahanam or Kamuni Pandaga or Kamani Pandagai. Some people say Holi is North Indian Festival but it is false, Holi is observed by all Hindus but in a different manner.
Odisha and West Bengal people celebrates this day as Dol Purnima, which is dedicated to lord Krishna.