3521 Manufacture of gas

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Includes

- production of gas for the purpose of gas supply by carbonation of coal, from by-products of agriculture or from waste
- manufacture of gaseous fuels with a specified calorific value, by purification, blending and other processes from gases of various types including natural gas [0]

Also includes

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Does not include

- production of crude natural gas, see 0620
- operation of coke ovens, see 1910
- manufacture of refined petroleum products, see 1920
- manufacture of industrial gases, see 2011 [0]

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