Former president Pranab Mukherjee and former prime minister Manmohan Singh paid tributes to former Delhi Chief Minister Sheila Dikshit who passed away today due to a cardiac arrest. She was 81. "It is great loss for the country and Congress party. Delhi has lost an outstanding leader and administrator who transformed the state beyond recognition. Country will remember her contribution towards the transformation of Delhi for a long time," Singh told ANI. Dikshit served the national capital as its chief minister for 15 straight years. Political leaders across party lines remembered Dikshit for her contribution to Delhi's development.