Sanjay Mitra, a 1982 batch IAS officer, on Sunday took over as new Chief Secretary of West Bengal, replacing Samar Ghosh who retired from the post. Mitra, who was holding the post of Principal Secretary of Health and Family Welfare department, would be replaced by Higher Education Secretary Satish Tewari. Mitra will enjoy a long stint in office as his retirement is due in 2019. Chief Minister Mamata Banerjee brought Mitra from the Prime Minister's Office some months after she took over in May last year.