In the absence of waste regulations and their rigorous implementation and enforcement, a generator of waste will tend to opt for the cheapest available course of action. For example, household solid waste may be dumped in the street, on vacant land, or into drains, streams or other watercourses, or it may be burned to lessen the nuisance of accumulated piles of waste. The uncontrolled burning of waste creates particulate and persistent organic pollutant emissions that are highly damaging locally and globally. Accumulated waste and blocked drains encourage vectors to breed, resulting in the spread of cholera, dengue fever and other infectious diseases and are a major contributing factor to flooding.