Multiple choice Swedish expert Falken Mark described water stress as a region with ample water resources but still facing water scarcity over-exploitation of water resources to expand irrigated areas and dry-season agriculture fall in ground water levels water availability lesser than 1,000 cubic metre per person per day water scarcity in low rainfall and drought prone regions Reveal answer Fill a bubble to check yourself D Correct answer Explanation This is the correct answer. According to Falken Mark, a Swedish expert, water stress occurs when water availability is less than 1,000 cubic metre per person per day.