Ahead of Republic Day, Old Secretariat lit up in tricolour in Bihar's Patna on January 25. Republic Day is celebrated to mark the day on which Constitution of India came into effect. On the other side, Kolkata Police headquarters, Raj Bhavan and The 42 also illuminated on the eve of Republic Day. Republic Day is celebrated on January 26 every year. Janata Bhawan, Gauhati High Court and Shraddhanjali Kanan also lit up on the eve of Republic Day in Assam's Guwahati.