Option 1: Agriculture refers to the practice of cultivating crops and raising livestock for food production. While agriculture can contribute to deforestation through practices like slash-and-burn farming, it is important to note that sustainable and responsible agriculture can actually help prevent deforestation.

Option 2: The building industry includes the construction of various structures. Although construction can contribute to deforestation, it is not a direct cause. Deforestation for construction usually occurs due to the demand for materials such as timber.

Option 3: Increasing population is indeed a cause of forest loss. As the population grows, the demand for resources increases, leading to deforestation for purposes like agriculture, housing, and urbanization.

Option 4: Tourism and pilgrimage can also contribute to forest loss, particularly in ecologically sensitive areas where large numbers of tourists can result in habitat destruction and increased pollution.

The correct answer is 3. Option 3 clearly identifies the increasing population as a significant cause of forest loss. Alert - correct answer should be 4.