At one site, Santiago Borden, 10, was straining to help, carrying a heavy jug of water over his shoulder. Eventually he gave up and passed the burden to his father.
“You’re a kid so you can’t expect to do everything,” his father, Abraham Borden, a lawyer and local politician, said to comfort him.
“I want to show solidarity,” Santiago said.
His father replied: “Of course you do. You’re Mexican, after all.”
The work has been nonstop since the earthquake struck. Overnight, whirring generators powered floodlights to illuminate the disaster scenes. And almost always, accompanying the rescue workers were volunteers clearing debris and distributing water, surgical masks and mustard-colored work gloves.
The scene at a collapsed building on Laredo Street took a grim turn shortly after dawn, as two bodies were unearthed from the wreckage. Still, work continued.
“We will continue to work to try and rescue everybody who lives in the building,” said Karen Piña, a doctor in charge of distributing medicine for the area.
Five people had been rescued, but there was still no word of Gabriela Jaén Pimienta, 43. Her uncle, Miguel Ángel Pimienta, had fainted with exhaustion as he waited for news on Wednesday morning.
His face covered by a surgical mask against the dust raised by the debris, he wept as he acknowledged the grim truth behind the wait.
“With every hour that passes, there is less possibility,” he said.
The work was taking its toll on rescue workers, pushing many to the breaking point. As dawn broke over two collapsed residential buildings in the middle-class neighborhood of Del Valle, rescue workers paused to rest as they waited for replacements. They believed 40 people were still trapped inside.
“There’s a breaking point, and we’re of no help like this,” said one government rescue worker with tears in his eyes. He asked not to be named because he was not authorized to speak publicly.
“I’ve been doing this 20 years, but it’s difficult to find people who almost made it out but didn’t,” he added. “There was a mother and daughter in a door frame and they were so close.”
But even where the daily routine returned, as dog walkers emerged in the early light and cafes opened to people scanning the news and messages on their phones, the unfolding tragedy, sometimes just blocks away, was evident.
Ambulance sirens interrupted the silence, and police trucks rumbled by. Volunteers carrying shovels headed to the rescue sites ready to take over from those who had been working all night.
Social media ricocheted with messages: photos of missing people, appeals for aid.
“Poor neighborhoods in Xochimilco and Iztapalapa without much help,” wrote Ricardo Becerra, an economist, on Twitter, referring to areas in the city’s south and east. “Come with picks and shovels.”
Over and over, variations on the list of supplies were repeated. Hammer drills, work gloves, helmets, electrolytes, IV fluid, adrenaline, insulin.
And through it all, there were notes of hope: “Found,” read one message on Twitter. “Leonardo Farías from the Enrique Rebsámen school.”
But the anguish was never far away. Leonardo, pictured in happier time wearing his knapsack and waving, was in the hospital. “He is in delicate condition,” the message said.