Which Eastern religion celebrates the festival of Guru Nanak Gurpurab on its founder's birthday?

Guru Nanak Gurpurab, also known as Guru Nanak's Prakash Utsav, celebrates the birth of the first Sikh guru, Guru Nanak (15 April 1469 – 22 September 1539). One of the most celebrated Sikh gurus and the founder of Sikhism, Guru Nanak Dev is highly revered by the Sikh community. This is one of the most sacred festivals in Sikhism, or Sikhi. The festivities in the Sikh religion revolve around the anniversaries of the 10 Sikh Gurus. These Gurus were responsible for shaping the beliefs of the Sikhs . Their birthdays, known as 'Gurpurab', are occasions for celebration and prayer among the Sikhs.

Sikhism is a religion originated in the Punjab region of the Indian subcontinent around the end of the 15th century. Sikhism is one of the youngest of the major religions and the world's fifth-largest organized religion, with about 25–30 million Sikhs as of the early 21st century.