2. In particular, the following categories of equipment must be used in the zones indicated, provided they are suitable for gases, vapours, mists, dusts or mists and dusts, as appropriate:
in zone 0 or zone 20, category 1 equipment,
in zone 1 or zone 21, category 1 or 2 equipment,
in zone 2 or zone 22, category 1, 2 or 3 equipment.