Bhubaneswar, Apr 17 (UNI) Strengthening the three-tier Panchayati Raj system and empowering women were among Biju Babu’s greatest contributions to Indian politics, BJD supremo Naveen Patnaik said on Thursday“No one can forget Biju Babu’s contribution,” Patnaik said while paying tribute to the legendary leader at Sankha Bhawan, the party office, on his 28th death anniversary.