Rashtriya Lok Dal (RLD) leader Ajit Singh joined the Union Cabinet on Sunday, with President Pratibha Patil administering the oath of office and secrecy to him at the Rashtrapati Bhavan. The Jat leader, who has been given the Civil Aviation Ministry, faces the challenge of reviving the aviation sector in general and the government-owned Air India in particular.

For the Baghpat MP, it is the fourth entry into the Cabinet. The RLD joined the Congress-led United Progressive Alliance (UPA) last week.

The RLD, which has presence in its traditional stronghold of western Uttar Pradesh, will contest the coming Assembly elections in the State along with the Congress, which is trying hard to revive its fortunes in India's most populous State under the leadership of party general secretary Rahul Gandhi.

Apart from Congress president Sonia Gandhi, Mr. Gandhi, who played a key role in finalising the alliance with the RLD, and Mr. Singh's son, Jayant Chaudhary, who is an MP from Mathura, also attended the ceremony.

With Mr. Singh's induction, the Cabinet strength now is 33 and the Council of Ministers 77. Notably, this is for the third time that it has been expanded in UPA-II.

The RLD is 15th party to join the UPA. The major constituents of the UPA are the Trinamool Congress, the Nationalist Congress Party and the Dravida Munnetra Kazhagam. With five MPs of the RLD joining it, its strength in the Lok Sabha is now 277.

The RLD was part of the BJP-led National Democratic Alliance in the 2009 general elections. It had earlier partnered with the Samajwadi Party and the Bahujan Samaj Party.

Son of the former Prime Minister, Chaudhary Charan Singh, Mr. Ajit Singh was a Minister in the P.V. Narasimha Rao-led Congress government, in the United Front government under Prime Minister V.P. Singh and later in the Atal Bihari Vajpayee-led NDA government.

The Civil Aviation Ministry was held by Overseas Indian Affairs Minister Vayalar Ravi after the elevation of Praful Patel as Cabinet Minister.

Mr. Ajit Singh's biggest challenge is to revive Air India, which is in a financial mess. He will also have to tackle issues such as growing operational costs, human resource optimisation and financial support, particularly after the Kingfisher Airlines episode.