- Samir Singh has been running between Mumbai slums and business district
- Mr Singh, 44, could only complete 114 km, falling short of his target
- Weighing 40 kg now, the marathon runner lost 16 kg during the challenge
Mr Singh, dubbed "The Faith Runner" and inevitably compared to Forrest Gump, spent nearly three months running between Mumbai's slums and business district using donated clothes and equipment, and living on just about Rs 190 a day.
At the end of his attempt on Sunday, the 5ft 7ins (170cm) running coach, who also suffered stomach problems and viral fever, weighed just 40 kilogrammes (88 pounds).
Mr Singh started on April 29 in scorching heat, and has been running through the monsoon rains without skipping a day. He needed to clock 150km (93 miles) on the final day on Sunday, after falling behind schedule through illness.
But the 44-year-old could only complete 114km, falling agonisingly short of his target -- which was the equivalent of about a quarter of the Earth's circumference.
"He was plagued by gastro-intestinal infections and contracted viral fever but has run 9,964.19 km in 100 days," Vikram Bhatti, who handled Mr Singh's campaign, told AFP.
"My journey of running 100 kilometres per day is very challenging but I wanted to show the endurance limit of human spirit," Singh told AFP ahead of the final run.
Friends mocked the man hailing from Madhya Pradesh for taking on the challenge, but it became an attempt that caught the public imagination.
"I survived without a job for the last nine months and people have come forward and supported me with donations, shoes, clothes and equipment," Mr Singh said.
He had a GPS watch, a basic mobile phone for emergencies and 200 rupees ($3.14) a day. Mr Singh said he particularly enjoyed his meal of rice and spicy lentils, after every run.
The five-time ultra-marathon winner lost 16 kilos (35 pounds) during the challenge as his exertions took their toll.
"I have focused on my goals with determination and nurtured my dreams despite cracked heels, fractured joints and legs," Mr Singh said.
Mr Singh was spotted one day by Mumbai documentary-makers Vandana and Vikram Bhatti, who christened him 'The Faith Runner'.
"We met him on the 47th day of his challenge and were taken aback by his story. So, we have been running a Facebook campaign to create awareness and generate funds for Samir," Vandana Bhatti told AFP.
Fans joined him for several stretches of his run each day.
Mr Singh's run was longer than the Great Wall of China (5,500km) and further than the distance from Mumbai to London (7,200km).
He went to a temple to pray on Monday, giving up a plan to complete the last 36 km.
Mr Singh said he will now rest, and then starting mapping out a new challenge -- this time over 40,000 kilometres.
"I have not met my mother for a while as she would be heartbroken looking at my sunken face. But I am happy so many people are invested in my story right now," Mr Singh said.