कौन-सी प्रमुख मानवजनित गतिविधि वायुमंडल में बड़ी मात्रा में सल्फर डाइऑक्साइड छोड़ती है, जिससे वायु प्रदूषण और अम्ल वर्षा होती है?

The 'Drain of Wealth' theory was propounded by which Indian nationalist leader?

Which event is considered the turning point in Mahatma Gandhi's leadership in the Indian independence movement?

Which African leader is known for his non-violent opposition to colonial rule?