Step 1: Understanding the Concept:
India has special bilateral agreements with some of its neighboring countries that allow for freedom of movement for their citizens across the borders without requiring a passport or visa.
Step 2: Detailed Explanation:
Due to a long-standing special relationship formalized by the 1950 Indo-Nepal Treaty of Peace and Friendship, Indian citizens can travel to Nepal without a passport or a visa.
A valid government-issued photo identity card, such as a Voter ID card or an Aadhaar card, is sufficient for entry into Nepal.
Similarly, Indian citizens can also travel to Bhutan without a passport, requiring only a valid photo ID.
However, travel to Bangladesh, Sri Lanka, and Pakistan requires a valid passport and a visa.
Since Nepal is one of the options provided, it is the correct answer.
Step 3: Final Answer:
Among the given options, Nepal is the neighboring country that Indian citizens can travel to without a passport or visa.