Step 1: Understanding the Concept:
This is a factual question regarding global public health milestones in India.
Step 2: Detailed Explanation:
After a sustained effort and mass vaccination campaigns, India achieved a significant milestone by remaining polio-free for a year.
The WHO officially removed India from the list of polio-endemic countries on February 25, 2012.
Step 3: Final Answer:
The correct date for India being struck off the polio-endemic list by the WHO is 25 February, 2012.