National Unity Day: 31st October

National Unity day (also known as Rashtriya Ekta Diwas) is celebrated every year on 31st of October by the people all through India. It is celebrated to commemorate the birth anniversary of Sardar Vallabhbhai Patel who really unified the country.
Rashtriya Ekta Diwas was introduced by the Government of India in 2014 with the aim of celebrating this event every year on 31st October.
 
Source- The Livemint