Sinha, an IAS officer of 1977 batch from Uttar Pradesh cadre, was Power Secretary before his new assignment. Earlier, he had served in different capacities at the Centre and in states.
Seth, a 1974 batch officer, was given a warm send-off by Prime Minister Narendra Modi who wished him all the best for his future.
"After a distinguished career spanning 4 decades, Cabinet Secretary Shri Ajit Seth retired today. Best wishes for the new phase in his life," Modi tweeted.
The Prime Minister also appreciated Seth's initiative for cleanliness.
"Ajit Sethji shared with me about 'Art in Steps', a unique initiative at Cabinet Secretariat to promote art & spread message of cleanliness," Modi tweeted.
