New explosives factories take time to support a Crete bombing campaign

Why not build explosives factories in India or Australia to supply bombers based on Crete?

Those factories would need years to develop the workforce, infrastructure and output required, so a large campaign would initially still depend on British bomb production.

Explosives factories in India and Australia would not immediately remove the need to ship bombs from Britain. A sustained bombing campaign requires the output of many factories, together with trained workers, supplies and supporting infrastructure that take years to establish. The illustrative calculation uses 200 Lancasters carrying eighteen 1,000-pound bombs apiece, creating a nightly ammunition requirement comparable to a destroyer's displacement. Producing and filling those large bombs also presents different handling demands from making smaller artillery shells. New factories could contribute as they developed, but British production would remain necessary while they built up capacity.