He replaced Haryana-cadre officer, Keshni Anand Arora, who was sent back to her parent-cadre.
Apart from UT Chandigarh, jurisdiction of the regional office extends to states of Punjab, Haryana, Himachal Pradesh and Jammu and Kashmir.
Ram Subhag Singh is currently on Central deputation and worked as Joint Secretary, Ministry of Defence, and then as MD, NAFED, a press release said.
In his previous stint with the central government, he worked as private secretary to the Ministers in the Food and External Affairs ministries, it said.