New Delhi: Monkey menace in the country has reached "epic" proportions and even derailed Prime Minister Narendra Modi's plans of making his parliamentary constituency Varanasi wi-fi enabled as they damaged optical fibre cables, a green body today said.

An investigation by 'Down to Earth', a publication of Delhi-based green advocacy group Centre for Science and Environment (CSE), said monkeys have been causing extensive damage to agriculture in India which was already facing low productivity due to extreme weather events.