The Assembly polls will be on February 8 and result will be out on February 11.
The manifesto may focus on clean energy, strengthening of the public transport system and increasing green area in the national capital.
"During the 1998-2013 Congress rule, plantation was carried out on a large scale, CNG buses were introduced and Metro work was prioritised to free Delhi from pollution," said Arjun Puri, Delhi Congress spokesperson.
The Congress is also likely to promise up to 400 units free power, which will cover 60 per cent of consumers. The AAP government has given up to 200 units free electricity.
The Congress is also mulling unemployment allowance for youth who could not find job despite being eligible.
Delhi Congress in-charge P.C. Chacko said, we would go to people highlighting the work done by late Chief Minister Sheila Dikshit.
Criticising the Aam Aadmi Party and the Bharatiya Janata Party, Randeep Surjewala said on Monday, "Delhi's development has been blocked due to the blame-game politics between the AAP and the BJP".
Surjewala said Dikshit led the government for 15 years in which five years were during the BJP rule at the Centre, but the development didn't suffer.
The Congress also pointed to vote data saying its share in the 2019 Lok Sabha polls increased to 22 per cent, while the AAP's share came down to 18 per cent.
( With inputs from IANS )