Moscow: Across the world's vast oceans, more tankers bearing crude oil from Russia have begun to sit idle, unable to find willing buyers amid declining demand.According to France24.com, estimates suggest that 19 million barrels of Urals crude loaded before December 15 are still in transit, as traders struggle to nail down buyers.Russia's revenue from oil and gas sales dropped by about a fifth last year, marking the lowest point in five years. This decline is attributed not only to a global glut of crude pushing prices down but also to a strong rouble, which means Moscow earns less in its own currency for each dollar from exports. Years of Western sanctions, including those targeting Russia's largest oil exporters, Rosneft and Lukoil, appear to be eating into Moscow's vital oil rents.Since the sanctions in October, the discount at which Russia sells its oil has doubled, with Urals crude falling below $40 a barrel in December. The outgoing Biden administration's sanctions on other major Russian oil expor ters have compounded the issue, placing four-fifths of Russia's oil production under US sanctions. These measures extend beyond the companies themselves, affecting anyone doing business with them.Alexander Kolyandr, a financial analyst, notes that secondary sanctions imposed by the US threaten companies receiving Russian oil with exclusion from US-run financial infrastructure. This has led to a reliance on smaller "teapot refineries" in China, which have less exposure to US sanctions.Targeting Russia's oil rents has been a core strategy of Western governments in response to Russia's invasion of Ukraine. The European Union and Group of 7 countries imposed a price cap on Russia's seaborne oil exports. Initially set at $60 a barrel, the cap will fall to under $44 a barrel on February 1. This measure aims to avoid a spike in oil prices while reducing Russia's revenue.To counteract these measures, Russia has turned to a "shadow fleet" of ageing tankers of unclear ownership. Recently, a French naval operation seized a tanker accused of financing Russia's war efforts, signaling an increased Western focus on this clandestine network.Both India and China, previously eager buyers of discounted Russian oil, appear more cautious in light of recent US sanctions. India has reduced purchase volumes, while China demands higher discounts. Lukoil, a major player in Russia's oil industry, is selling overseas assets to US private equity firm, the Carlyle Group, potentially increasing Russia's foreign reserves despite decreasing oil profits.Russia faces difficult economic choices as oil and gas revenues shrink. The federal budget deficit stood at 2.6 percent of GDP last year, prompting the government to raise domestic taxes. Economic growth has slowed, and social spending has been slashed, with potential impacts on either the war effort or social welfare.Despite the economic pressures, Kolyandr suggests that President Putin's focus on geopolitical priorities makes it unlikely that the sanctions will deter Russia's ongoing conflict in Ukraine. The war remains a priority, even as the Russian economy faces significant challenges.