Former Samajwadi Party leader Amar Singh has died after battling an illness. He was 64. The Rajya Sabha MP had gone to a hospital in Singapore in March for surgery in a kidney-related illness. Amar Singh was a key leader in the Samajwadi Party at a time when the party moved to support the Congress-led United Progressive Alliance (UPA) government in 2008, after the Communist Party of India withdrew from the government over a nuclear deal with the US.