Which of the following statement is not incorrect ?

Options

A. In the 1990s, Delhi ranked fourth among the 40 most polluted cities of the world.
B. All the buses of Delhi were converted to run on CNG by the end of 2000.
C. Euro III norms , for example , stipulate that sulphur be controlled at 350 parts-per- million (ppm) in diesel and 150 ppm in petrol.
D. Mass Emission Standards (Bharat Stage II which is equivalent to Euro - II norms) are applicable in all cities of India.

Answer

To solve the question, we need to evaluate each of the four statements provided and determine which one is not correct. Here’s a step-by-step breakdown of the solution:

### Step 1: Analyze the First Statement
The first statement claims that "in the 1990s, Delhi ranked 4th among the 40 most polluted cities of the world."
- **Evaluation**: This statement is correct. Historical data indicates that Delhi was indeed among the most polluted cities globally during that time.

### Step 2: Analyze the Second Statement
The second statement mentions that "all the buses of Delhi were converted to run on CNG by the end of 2000."
- **Evaluation**: This statement is also correct. The conversion of buses from diesel to Compressed Natural Gas (CNG) was a significant step taken to combat air pollution in Delhi.

### Step 3: Analyze the Third Statement
The third statement states that "Euro third norms for example stipulate that sulfur be controlled at 350 parts per million in diesel and 150 parts per million in petrol."
- **Evaluation**: This statement is incorrect. The sulfur limits mentioned correspond to Euro second norms, not Euro third norms. Euro third norms have stricter limits.

### Step 4: Analyze the Fourth Statement
The fourth statement claims that "mass emission standards, which are equivalent to India's second stage, are now applicable in all cities of India."
- **Evaluation**: This statement is correct. Mass emission standards have been implemented across various cities in India to regulate vehicle emissions.

### Conclusion
After evaluating all four statements, we find that the third statement is the only one that is not correct. Therefore, the answer to the question is the third statement.

### Final Answer
The statement that is not correct is the third one regarding Euro third norms.

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