The streets of Gaza are busy, but they are also crumbling.

Since Hamas took control of the Gaza Strip in 2007, Israel has maintained tight limits on shipments of anything that could be used for military purposes. That includes basic building materials that could be used for bunkers and rocket launching sites.

Ask businessman Ali Abdel Aal what's the toughest thing for him to find, and he'll tell you "cement and gravel."

Abdel Aal runs a busy shop selling building supplies in Gaza City. He says tunnels from Egypt help get around the Israeli restrictions. But even that route is getting pinched. Egypt has started flooding these illegal pathways with water, even with sewage.

Two years ago, Israel shut down a freight crossing close to Gaza City. That means the only legitimate route Abdel Aal can depend on is Kerem Shalom, an hour away from his shop in Gaza City.

"From Kerem Shalom we have to bring it to Gaza, which costs too much for transportation," Abdel Aal said.

Israeli authorities insist that since the November ceasefire, they have added item after item to the list of goods they will permit into Gaza. Israeli army Lt. Col. Avi Shalev says more than 300 trucks a day pass through Kerem Shalom.

"There is no shortage of building materials in the Gaza Strip. There is a building boom in Gaza," Shalev says.

And it's true, you can see buildings going up all over Gaza. At a construction site in Gaza City, cement is pumped up to a rooftop, where workers peer down, wearing no hard hats or lifelines.

But many here say all this activity can't keep up with Gaza's rapid population growth, or with the need to replace buildings destroyed in Israeli military operations.

Adnan abu Hasna of the United Nations Relief and Works Agency says he is struggling to provide homes for refugees from past conflicts.

One example is a huge housing project financed by the Saudi government in the southern Gaza Strip. Waji el Jebaley, 29, is moving into the shiny new development with his family. Ten years ago, el Jebaley, who works as an accountant, lost his home in a military operation. Back then, he and his family asked the U.N. for space for six people.

Now that he and his brothers are married, he and his extended family have more than doubled to 17.

There's one effect of the blockade that you can't see, unless you look in people's pockets. The tightening of the borders to Israel and to Egypt has also made it very difficult for local businesses to export.

Gaza used to be a big agricultural producer. Now, Gazan farmers like Basel Abu Haloob say they're operating at a loss. Abu Haloob is not allowed to export to Israel or to the occupied Palestinian West Bank.

"I'm not dreaming about selling to Israel. Let them allow us to sell to [the] West Bank," Abu Haloob said. "The market here in Gaza, it's very cheap."

Two pounds of strawberries sells for under a dollar; they can cost three times that much in Israeli cities. And that, of course, is the point of the Israeli sanctions — to starve this Hamas-run territory of resources.