CAIRO – The pile of trash overwhelmed the median divider on Ahmed Zaki Street and spilled into oncoming traffic – egg shells, rotten eggplants, soiled diapers, bottles, broken furniture, junked TV sets. Flies swarmed and the summer sun baked up a powerful stench.

Then Kawther Ahmed and her mom came out to add their plastic bag of household trash. The garbage collectors hadn’t been by for two days, said Ahmed, 25, and the metal trash bins in the lower-income Cairo neighborhood, called Dar el-Salam or “House of Peace,” had disappeared, probably sold for scrap metal.

“What can we do?” she asked. Egypt’s newly elected president, Mohammed Morsi, is under growing pressure to answer that question.

He already faces a host of challenges: from secular Egyptians worried about his Islamist doctrines; from militants trying to stoke conflict with Israel, and from the poverty and joblessness that fed the Arab Spring and brought down the three-decade dictatorship of Hosni Mubarak.

To all those, add the rising tide of garbage in Cairo, the world’s largest Arab city. Morsi declared it one of his top five priorities, promising to clean up the streets within 100 days. In so doing, he gave the electorate a powerful way of measuring his abilities, and it looks increasingly certain that 100 days will be nowhere near enough.

Cairo’s waste management problem began to get acute a decade ago as the capital’s old system, simple but reliable, became swamped by population growth. A government modernization effort flopped.

A swine flu panic prompted the mass slaughter of the pigs that recycled Cairo’s organic garbage; the city’s metal trash bins were easy prey for thieves, especially during the global scrap metal boom.

In Dar-el-Salam, as in many other parts of the city of 18 million, there is no one to hold back the “nabasheen,” the diggers – young men and women who rummage through the bags of plastic, glass and cardboard and leave the organic stuff to rot in the streets.

Morsi is wading into a landfill of interwoven problems. Rival collectors vying for the big business of trash fight over turf that used to be parceled out in an orderly way among a fixed number of garbage-collecting clans.

Layers of corrupt and inefficient bureaucracy choke the system. The collapse of police forces in the revolution in early 2011 means that no one is enforcing what few rules there are.

As a result, Cairenes end up dumping much of their daily output of 17,000 tons of garbage on the street.

“We have designed an unsustainable system for the city,” said Laila Iskandar, an expert in waste management. “It is a chain, and no one thinks of the chain. Only the end point ... Out of sight out of mind.”