Sour gas is coming to the fore. IOCs are targeting a greater gas mix in their portfolios, meanwhile many NOCs are looking for strategic domestic supply. From the Middle East to Central Asia, the biggest and boldest upstream projects must deal with sour gas and its toxic hydrogen sulphide impurities – whether associated with oil or non-associated. Sour gas output will increase by over 50% in the next decade, supplying almost 10% of global gas and shaping sulphur's US$10 billion-a-year market. That excludes the growing volumes re-injected at oil megaprojects.