In which Indian state was the country's first Green Rail Corridor recently launched, marking a major step towards environmentally friendly train operations?

Introduction / Context:
This question relates to environmental initiatives taken by Indian Railways, specifically the launch of the first Green Rail Corridor. A Green Rail Corridor is a railway section where trains run with zero discharge of human waste onto the tracks due to the use of bio toilets and associated sanitation measures. Awareness of such initiatives is important for examinations that test knowledge of sustainable development, infrastructure, and government programmes in India.

Given Data / Assumptions:
The problem states that India has launched its first Green Rail Corridor and asks in which state it was introduced. The answer choices are:
- Karnataka
- Maharashtra
- Himachal Pradesh
- Tamil Nadu
It is assumed that the learner has basic knowledge of recent railway initiatives and understands that the Green Rail Corridor refers to a specific route rather than the entire network.

Concept / Approach:
A Green Rail Corridor focuses on maintaining cleanliness along the railway track by ensuring that trains running on that section have fully functional bio toilets so that human waste is not discharged onto the rails. Indian Railways launched the first such corridor on the Manamadurai to Rameswaram section in the state of Tamil Nadu. Therefore, the correct answer is determined by recalling which state hosts this pioneering corridor. The other states listed in the options have important railway routes, but they were not the location of the first officially declared Green Rail Corridor.

Step-by-Step Solution:
Step 1: Recall what a Green Rail Corridor means; it is a stretch where all trains are equipped with bio toilets to prevent direct discharge of waste on tracks. Step 2: Remember the specific section that was first declared a Green Rail Corridor by Indian Railways, namely the Manamadurai to Rameswaram route. Step 3: Identify that both Manamadurai and Rameswaram are located within the state of Tamil Nadu in southern India. Step 4: Match this information with the given answer choices and locate Tamil Nadu among them. Step 5: Select Tamil Nadu as the correct state because it hosts the specific section that was declared India's first Green Rail Corridor.

Verification / Alternative check:
If a learner is unsure, an alternative way to verify is to connect Rameswaram with the state map of India. Rameswaram is a well known pilgrimage town situated on Pamban Island in Tamil Nadu. The corridor between Manamadurai and Rameswaram therefore lies entirely in Tamil Nadu. No similar announcement of a first Green Rail Corridor was associated with Karnataka, Maharashtra, or Himachal Pradesh, even though those states also have railway lines. Because government press releases and news reports specifically mention the Tamil Nadu section as the first, this corroborates Tamil Nadu as the correct answer.

Why Other Options Are Wrong:
Karnataka: Although it has important routes and major stations like Bengaluru, it was not the location of the first Green Rail Corridor.
Maharashtra: This state has a dense railway network including Mumbai, but the pioneering corridor was not launched here.
Himachal Pradesh: Famous for hill railways such as the Kalka Shimla line, but it was not involved in the first Green Rail Corridor project.

Common Pitfalls:
A common mistake is to guess Maharashtra or Karnataka because they are large and industrially advanced states with significant railway traffic. Another pitfall is confusing the concept of Green Rail Corridor with other environmental initiatives such as solar powered trains or cleanliness campaigns, which may occur in different states. To avoid such confusion, remember that the specific phrase first Green Rail Corridor is directly linked to the Manamadurai to Rameswaram section in Tamil Nadu.

Final Answer:
India's first Green Rail Corridor was launched on a route in the state of Tamil Nadu.