Oil prices experienced their biggest one-day percentage decline since early January, with Brent futures and West Texas Intermediate crude falling around 5% to a five-week low. The fall was fueled by increased concerns about the economy as US politicians discuss ways to avoid a debt default and investors prepare for more rate hikes this week. Additionally, US Treasury Secretary Janet Yellen warned that the government could run out of money within a month. The fall in oil prices was also impacted by the expected interest rate hikes by central banks, which could slow economic growth and dent energy demand. The US Federal Reserve is expected to increase interest rates by another 25 basis points, while the European Central Bank is also expected to raise rates at its regular policy meeting later this week.