* Quality data shows improved quality for Urals export

* Asia demand up as flows to EU slow in wake of sanctions

* Russia heavily discounting its Urals for Asia buyers

MOSCOW, June 27 (Reuters) - Russia has been improving the quality of its flagship Urals crude oil export, making the heavily-discounted grade even more attractive to buyers in Asia who have been snapping it up, data obtained by two industry sources and seen by Reuters showed.

Russian oil exports have been strong despite Western sanctions as China and India ramped up purchases and U.S. officials have said Moscow was now earning more money than before the conflict in Ukraine because of higher oil and gas prices.

It has been changing the Urals blend to make the oil lighter and sweeter during the last three months despite a ban on imports of technology for the oil and gas industry from the West, the daily quality data viewed by Reuters on Monday showed.

Russian oil pipeline monopoly Transneft, which transports most of the crude via its system and is responsible for quality control, did not respond to a Reuters request for comment.

China and India have become major buyers of Russian oil in the last two months as Moscow seeks other markets for its cargoes as flows to the European Union have slowed ahead of a ban expected to take effect at the end of the year.

Two traders who spoke to Reuters on condition of anonymity because they are not allowed to speak to the press, cited lower domestic demand for low-sulphur oil as one of the reasons that has seen an improvement in the quality of export Urals.

Several plants in Russia's south, which are usually large buyers of low-sulphur oil, have reduced operations in recent months because EU customers are no longer buying Russian oil products or due to logistical issues related to proximity to the Ukrainian border.

SULPHUR CONTENT FALLS

Urals oil loading from Primorsk port is sweeter with the sulphur content falling to 1.59% for cargoes loading in May-June on average, while in January the content from the cargoes was at %1.64 on average, according to the sources' data. The crude was also slightly lighter with an average gravity of 30.1 degrees API in May from 29.8 degrees in January.

API gravity is a commonly used scale for measuring the density of crude oil. Higher numbers correspond to lighter crude.

Urals oil volumes loading from Ust-Luga and supplied to Europe via the Druzhba pipeline have also seen sulphur content slip to %1.66 on average in May-June from above %1.7 in January this year. Gravity rose slightly, from 30.3 degrees API to 30.6, according to the data.

Urals oil exported from Black Sea Novorossiisk was also sweeter in May-June compared to January, according to the data. Sulphur content in these barrels fell to 1.42% from 1.55% early in the year. The crude was also lighter: gravity rose to 30.65 degrees API in June from 29.5 in January.

Possible quality change also could come from curbs to oil production on certain fields, which provide lower quality crude, two other traders said.

"We saw a decline of output in Bashkortostan and Tatarstan regions that produce high-sulphur heavy oils in April-May, which could help the quality", one of the traders said.

Russian oil output was down in April following sanctions on the country's financial sector and a sharp fall in demand from European buyers, but has been recovering since May.

(Reporting by Reuters; Editing by Emeiia Sithole-Matarise)