Congress leader Ajay Maken takes a picture as former Prime Minister Manmohan Singh and his wife, Gursharan Kaur, launch the party's app.
The ruling BJP has emerged as the world's largest party, disclosing over the weekend that it now has 8.8 crore members.
The Congress, which accumulated its worst-ever result in the national election, has today launched what is described as an "online and app-based" membership drive.
The initiative was launched by former Prime Minister Manmohan Singh, whose coalition government was voted out in May last year. In the most recent Delhi election, the Congress did not win a single seat in the city-state it governed for 15 years.
"The last date for becoming a member is May 15," said senior Congress leader Ajay Maken, who was the party's chief ministerial candidate in the capital. " You can apply on the internet. We also have Android-based application and iPhone based application."
The BJP's president Amit shah is expected to announce the record membership of his party tomorrow. A crore signed up just in the last eight days, sources say, as part of a four-month initiative that allowed people to become members by dialing a phone number.