Today is the second day of Deepawali festival. It is called Narak Chaturdashi or Choti Diwali. It is celebrated on 14th day of dark fortnight of Kartik month in Vikram Samvat Hindu calendar.
It is believed that asura (demon) named Narakasur killed on this day by lord Krishna. There are different beliefs behind these festivals in different parts of India.
Each festival holds spiritual significance.
P.S. In this photograph my mommy is doing pooja.