The City of Cape Town, not for the first time, wants to re-draw the "urban edge" - a hypothetical designation of where urban development must stop, in order to protect the agricultural land beyond it. The City proposes handing over almost 300 hectares in the agricultural area of Philippi in order for private developers to build houses on it. Opponents argue that Cape Town can't afford to lose the fresh produce, or harm the water source that lies beneath the land. On Wednesday, the rezoning of the farmland came one step closer to becoming a reality.

Philippi is 20 minutes' drive from Cape Town city centre. It's not particularly scenic, but it punches above its weight in terms of its importance to Cape Town. The area is estimated to produce about half the carrots, cauliflower and lettuce supplied to the city, in addition to crops like cabbages and leeks: in total, just under 100,000 tons of fresh produce per year. Philippi produce supplies supermarkets, but also low-income Cape Flats households through informal traders. The area also lies on a valuable aquifer.

Between 1998 and 2012, the M&G reported last year, the 3,200 hectares designated for horticultural use...