Oil prices fell by almost 3 percent Tuesday, dipping below $64 a barrel as worldwide demand and supply threats ease. After a seven-day selloff, crude futures are at their lowest level since late March. Light sweet crude for October delivery fell $1.85 to settle at $63.76 a barrel on the New York Mercantile Exchange - the lowest closing price for front-month futures since finishing at $61.77 a barrel on March 22. Nymex oil futures have fallen every day the exchange has been open in September. On Monday, the Organization of Petroleum Exporting Countries said it will keep pumping crude at current levels, while also making clear it would consider scaling back production if oil prices keep plummeting.