Mahatma Gandhi was criticizing the negative impact of a specific action or policy carried out by the colonial government in India. Based on the provided options, the correct answer is option 1: Salt tax.

Gandhi believed that the salt tax imposed by the British colonial government in India had detrimental effects on the Indian population on multiple levels. He argued that this tax not only imposed a financial burden on the people but also symbolized their subjugation to colonial rule. The salt tax made it difficult for ordinary Indians, particularly those living in poverty, to afford a basic necessity like salt.

Furthermore, Gandhi believed that the salt tax eroded the cultural and spiritual fabric of Indian society. Salt has a significant symbolic value in Indian culture and plays a crucial role in religious practices and rituals. By monopolizing the production and sale of salt, the colonial government undermined these cultural practices and the sense of Indian identity.

Gandhi`s protest against the salt tax, famously known as the Salt Satyagraha or the Dandi March, became a significant event in the Indian independence movement and highlighted the oppressive nature of British colonial policies.