SAN LUIS — Eduardo, 14, crosses his legs and swings them under the dining table. He pokes at the royal-blue putty he has just mixed up, staining his hands. Gel shapes his black hair into peaks.

His chubby cheeks perk up when he smiles. He is a child whose innocence has been shaped by an unusual daily routine: crossing Mexico to the United States to go to junior high school. But some local residents and teachers are pushing to crack down on students like Eduardo, arguing they are a key reason for increasingly crowded schools.

It’s a Saturday afternoon, and he’s discussing high school options with his mother, Alicia. He keeps poking at the putty; the stains on his fingers darken. She sips cool, sweet tea. They’re in their compact home in San Luis Río Colorado, the Mexican twin city of San Luis.

She suggests Yuma Catholic High School in nearby Yuma but hopes her son shuts down her suggestion. She can’t afford “la Católica.”

He shuts it down.

Alicia pitches the idea of Kofa High School in Yuma, 20 miles north of the border.

“Hmm,” Eduardo says, looking up. He’ll consider it.

A few years ago, Eduardo, a U.S. citizen who was born in Yuma but who has lived all of his life on the Mexican side of the border, had no doubt that he eventually would enroll in San Luis High School, just two miles past the line dividing the country where he lives from the country where he was born.

But now, in the spring semester of eighth grade, he isn’t so sure about San Luis High. The word was, because of overcrowding, registration requirements would tighten. The Yuma Union High School District had received complaints blaming the crowded conditions on students who live in Mexico — students like Eduardo.

Eduardo, who real name is not being used by Cronkite News to protect his identity, is one of thousands of children who teachers and administrators estimate live in border towns in Mexico and attend schools in Arizona, California, Texas and New Mexico. In other parts of the country, away from the interconnected world that is the U.S.-Mexico border, Eduardo’s daily routine might sound dangerous because of the crush of people trying to cross the border and potential interaction with criminals trying to smuggle drugs into the U.S.

But along the U.S.-Mexico border, living in one country and going to school in the other has been part of everyday life for decades, local residents say.

In San Luis, where most jobs are in the fields that produce 90 percent of all leafy greens consumed in the winter in the United States, another dynamic is at play.

Many parents and teachers are debating whether children who live in Mexico should have a right to public education in the United States, even if they’re U.S. citizens.

“Those students who cross the border daily take advantage of the public school that we have available for them,” said Malba Alvarez, a mother of three who teaches criminal justice at San Luis High.

Alvarez, a naturalized citizen from Mexico, is one of the people who have been airing their frustrations at public meetings and to anyone who will listen. She estimates enrollment in the district would drop 40 percent if it enforced its district residency requirements.

Yuma Union High School District administrators are trying to find out how many of the district’s students live in Mexico. The problem is that the paperwork for every student enrolled in the district school lists an address in Yuma County, thus enabling to the student to enroll.

To enroll in San Luis High, for example, a student must show proof of Yuma County residency. Students residing in Mexico usually provide a utility bill from a relative living in the district and a notarized letter stating that he or she lives with that relative.

While the debate continues, Eduardo’s life goes on as it has since he was 6, when he first walked across the border with his older brother to attend Ed Pastor Elementary School in San Luis.

For most of those years, his routine has been the same: He wakes up at 4:30 a.m. and gets ready for his mom to drive him to Hotel Internacional, across the street from the San Luis Port of Entry, the legal gateway between Mexico and the United States. He gives her a kiss before hopping out of her white SUV.

Eduardo crosses the street and dodges the vehicles waiting in line to get to “el otro lado,” the other side, as the U.S. side of the border is commonly known. The people in these vehicles might wait an hour or more before they can cross. There are parents driving their children to school and workers driving to their jobs in the United States.

In the pedestrian line, it’s mostly fieldworkers and students, and it can stretch up to three blocks. Eduardo is there, shuffling along toward the border crossing.

The sun isn’t up yet, but the line is alive.

If multiple customs officers happen to be working in the morning, it’s a good day: It only takes Eduardo an hour or so to cross. If there are only one or two officers, his wait extends for an hour and a half.

Eduardo is used to the routine, and he’s prepared for the typical ordeals that arise from the time he steps out of his mom’s car to when he steps onto the school parking lot. Being questioned by the occasional tough Customs and Border Protection agent is normal, as is waiting in line for more time than it takes to get through first period at school. On some Mondays, a shorter school day, he misses first period entirely because it lasts only 30 minutes.

Last winter, however, crossing the border came with a whole new challenge.

Winter is lettuce season, and thousands of workers every morning compete with students to make it to their fields on time. The average number of pedestrian crossings in the San Luis Port of Entry was nearly 8,400 daily in December, nearly 3,500 more than in July, the slowest time of the year, according to data from the Bureau of Transportation Statistics by Eller College of Management at the University of Arizona.

Often, students who are running late cut the line, causing an uproar. Usually, retaliation amounts to whistling and shouted curses in Spanish. But one morning in December, Eduardo and his mother recalled, the whistling turned to shoving and yelling. Children were squeezed between workers. An elderly woman selling candy reportedly was pushed to the ground, her sweets scattered across the concrete.

The push-and-shove became known as an avalancha — an avalanche — turning the line of pedestrians into a mosh pit.

Eduardo said avalanchas have happened several times since, the most aggressive pushing and shoving to the front of the line while the more cautious stay back, at the expense of missing their ride to the fields or getting detention at school for showing up late.

“Even though I didn’t like it, I had to run to the front,” Eduardo said. “It’s something that I had to do.”

He remembers seeing young children in uniforms stuck in the mosh pit and falling to the pavement. Eduardo thought back to when he started crossing alone at their age. He doesn’t remember anything like an avalancha happening when he was little.

Eduardo experienced avalanchas twice last winter before his mom decided it was too dangerous for him to cross alone. Now she often drops him at the hotel and he hops in his father’s car, which, by then, has been in line for a while. His father, who has been separated from Alicia for years, lives in Mexico and drives Eduardo and his half-siblings to the other side, where he works.

It takes a group effort to get Eduardo to school.

On the Arizona side of the border, along San Luis’ bustling commercial center, taxis line up on one street, waiting for students, and faded white buses line up on another, waiting to transport field hands. Food trucks, known in Spanish as “loncheras,” have been busy since 3 a.m. Men and women of all ages stay warm with a burrito or a cup of “birria,” a spicy goat or chicken stew, before the bus doors open and they’re allowed to board.

There also are vans for hire that gather on Urtuzuastegui Street, the first street encountered upon entering the United States. By 6:30 a.m., they are full of uniformed children, mostly bound for San Luis Middle School, Southwest Junior High School and San Luis High.

Eduardo has his own trusted driver. The van fills quickly and heads off to school. Each student hands the driver a dollar before jumping out. He repeats the trip until a little after school starts, and he’s back at it when school ends, taking students in the opposite direction.

Eduardo goes to Southwest Junior High, which already feels overcrowded.

“It’s uncomfortable, honestly, to have to sometimes be squeezed in a classroom,” he said.

He can’t imagine what it must be like at San Luis High. He’s heard that the classrooms there have a lot more students and that despite three lunch periods, students sometimes don’t get lunch because there isn’t time to feed them all.

Such conditions are why parents in the Yuma school district complain.

Teachers have as many as 47 students in a single class, according to records provided by San Luis High, which has 500 more students this year than four years ago, a 20 percent increase.

More than 3,000 students enrolled at the high school for the 2017-18 year. Most of them come from San Luis, which has about 32,150 residents, but also from small surrounding communities, including Somerton and Gadsden.

Alvarez, who teaches at San Luis High, said she can identify the students from Mexico in class. They usually are those falling asleep, showing up late or not at all to first period, and ultimately, failing her class because they’re too tired to focus, she said.

“Some (students) don’t hide it, and they’ll tell you,” Alvarez said. “Some are more reserved and keep it to themselves. They’ll protect their families that way.”

The district does not require teachers to report students they suspect live in Mexico.

David Lara, a member of the district’s governing board and self-proclaimed “community watchdog,” has unsuccessfully spent years fighting for legislation that prohibits the daily crossing of students from Mexico. He believes former Superintendent Toni Badone, who led the district for 10 years, intentionally ignored the overflow of students and efforts to dodge residency requirements.

“What I found was that the school district doesn’t want to do anything about it because it is a headcount,” Lara said. “It’s money.”

Lara said his concerns are not just about money. Students crossing an international border by themselves, in the dark, is a safety hazard, he said. He brought up the point to the San Luis City Council, but so far, it has not taken action.

Georgina Thompson, the new district superintendent, said the district cares about the safety of students, but it hasn’t been asked to help seek a solution to children crossing the border.

“The city of San Luis hasn’t asked for a letter from us. The Border Patrol hasn’t asked us to get involved. The FBI isn’t asking for support,” she said.

Thompson grew up in Yakima, Washington, where she worked summers picking vegetables and packaging them until she dedicated her life to teaching and eventually education administration. She became interim superintendent in October after Badone stepped down and was hired permanently in February.

Thompson said she made tightening the enrollment process a priority after hearing parents’ complaints, but overcrowded classrooms are not a new issue — every generation of teachers believes it has things worse than the one before. She had 42 students in her classroom when she taught at Cibola High School in Yuma in 1989.

The statewide teacher shortage also contributes to the overcrowding; she noted that the district has 24 unfilled teaching positions.

Thompson said she has found the district knowingly accepted false documentation for enrollment, but staff shortages had led to cuts in verification efforts. A school resource officer who verified addresses was laid off a few year ago because of budget cuts.

Despite the false documentation, Thompson said she has no intention of expelling students or blocking their continued enrollment. But she believes parents living in Mexico should pay tuition for their children schooled in the U.S., which is a requirement in Arizona.

Tuition for the 2017-18 school year at San Luis High is more $4,600 per student and can be paid in monthly installments. As of March, nine students in the district paid tuition, including three at San Luis High. Eduardo and his mom said they never knew paying tuition was an option, but at any rate, Alicia said she can’t afford it.

Thompson said the district has met with the parents of more than 300 students who hope to enroll in for the upcoming school year. They are being asked to prove their district residency or pay tuition, prompting accusations that Thompson is tossing kids out of school.

Cronkite Borderlands Project is a multimedia reporting program in which students cover human rights, immigration and border issues in the U.S. and abroad in both English and Spanish.