MOSCOW, May 7. /TASS/. Crude oil transit over the Druzhba pipeline running across the territory of Ukraine has declined over a four-month period this year due to consumer complaints regarding oil quality, Official Spokesperson of the Russian oil pipeline operator Transneft Igor Dyomin told TASS on Monday.

"The decline over the northern branch of Druzhba came to 1.4%, while over the southern one it amounted to 18% to Hungary and 8% to Slovakia," Dyomin said. Supplies to Hungary fell by 280,000 tonnes and to Slovakia by 130,000 tonnes in four months of this year," the spokesperson emphasized.

Hungarian consumers pointed out the consumption reduction in the quality of Russian oil by explaining that they would like to have 1.5% of sulfur content rather than 1.75%, Dyomin said. "This is within the standard but they are not satisfied with such quality," he noted.

Oil transit via Ukraine declined by 9.3% to 4 mln tonnes in January - April 2018, the Ukrainian pipeline operator Ukrtransnafta said earlier.

In consultations held with oil companies, Transneft and the Russian Energy Ministry on the content of sulfur in oil exported via the Druzhba oil pipeline make it possible to expect that the quality of oil supplied over this pipeline will not change in 2018, deputy head of the Federal Antimonopoly Service of Russia Anatoly Golomolzin said earlier. The standard for the maximum sulfur content of the Urals oil blend is currently equal to 1.6%.

Several major oil blends currently exist in Russia: heavy Urals with its price calculated with the discount to Brent, Siberian Light, and ESPO (East Siberian oil blend). Other Russian oil blends are REBCO, Sokol (Sakhalin 1), Vityaz (Sakhalin 2), and the Arctic blend ARCO from the Prirazlomnoye Field.