Darjeeling: Suresh Zimba, 38, an assistant commissioner with the state tax department, could not engage in any physical activity in 2015 following a nerve compression.

On a doctor's advice "that the primary goal in treating nerve compression is to relieve adverse forces on nerves", the boy from Badamatam tea garden in Darjeeling decided to start running.

On Sunday, Zimba will be running the 90.184km ultra marathon in South Africa, hoping to complete the run within the stipulated 12 hours.

The Comrades Marathon, which was first started in 1921 by a veteran, Vic Clapham, in memory of all the South African soldiers who had laid their lives for the country, is considered among the most difficult in the world.

The run will start from City Hall in Pietermaritzburg and end at the Moses Mabhida Stadium in Durban.

"We have to complete the run within 12 hours but I am hoping to complete within 8-9 hours. It is ASIJIKI for me," Zimba told The Telegraph from South Africa.

ASIJIKI is the theme of this year's run and means, no turning back, in local language.

Zimba has not turned back since 2015. "The pain was excruciating and I was disabled to the extent of not being able to do any physical activities. I decided to heed my doctor's advice and decided to start running," said Zimba.

The tax official has so far participated in marathons in Hyderabad, Delhi, Mumbai, Calcutta, Makyrwat ultra marathon in Meghalaya and host of other marathons in the country by funding his participations through "personal savings."

To prepare for the Comrades marathon, Zimba and his American friend Ijeoma have covered the 72km stretch from Siliguri to Darjeeling early this year.

"However, I am always running, preparing. I do six days of running and strength training every week. To be precise, one can say I have been preparing for this South Africa run for 19 weeks and have covered 1400km," said the father of two.

Running has now become a passion for the official. "I think I am the first government official from Bengal to participate in this Comrades Marathon," said Zimba.

Over 20,000 runners from more than 60 countries will be participating in this year's run.

Zimba's wife Srijana will be there to cheer him in South Africa.

"My family has always been supportive and stood by me in difficult times. They have cheered me all along and I am excited to fulfil my dream. Running is now a passion for me," said Zimba.