Union Minister Giriraj Singh on Sunday said Bihar Chief Minister Nitish Kumar has been regretting his decision to leave the Bharatiya Janata Party-led National Democratic Alliance.Singh said Nitish Kumar is regretting the move as he is now alone and under tremendous pressure to run the Bihar government with Rashtriya Janata Dal (RJD) of Lalu Prasad."BJP did not dump Nitish Kumar in 2013. It was Nitish who walked away from the BJP-led NDA due to his high ambition," Singh, the Union Minister of State for Micro, Small and Medium Enterprises, said."But for Nitish Kumar's decision to leave NDA to realise his political aimbtion, there is no vacancy for the top as Narendra Modi is Prime Minister and will continue after 2019. Now, Nitish Kumar has been regretting," the minister said.Singh said the Bihar chief minister has already lost his face of governance and development."When he was Chief Minister of Bihar in alliance with the BJP and when he was union minister in Atal Bihari Vajpayee-led government, Nitish was known for his governance and development... not anymore now," he said.The Union Minister also downplayed the question if Nitish Kumar, the Janata Dal (United) President, was likely to return in the NDA fold in near future.Singh is the BJP's Lok Sabha member from Nawada constituency in Bihar.