The Biden admin is turning a lower percentage of border crossers back into Mexico

Biden administration officials say their new immigration policies have discouraged many migrants from trying to cross the border since the Covid ban known as Title 42 ended in May.

But an NBC News review of border crossing data shows that the Department of Homeland Security is also expelling fewer migrants per day back to Mexico than it was in the last full month before the end of Title 42.

On average, about 1,000 migrants have been sent back across the border into Mexico since Title 42 ended May 11, compared with nearly 3,000 a day in April.

As a proportion of total border crossers, about 14% of undocumented migrants caught crossing into the U.S. each day in July were sent back into Mexico, down from a daily average of 32% in April.

Under Title 42, migrants were sent back to Mexico without having the chance to claim asylum in the U.S.; the Trump and Biden administrations said it was to curb the spread of Covid. In its three years of existence, it blocked more than 2 million border crossings.

But as the policy neared its end, it could not actually be used to block most would-be border crossers. Mexican shelters began to get overcrowded and refused to take back people of certain nationalities. More than 10,000 undocumented migrants a day were crossing into the U.S. in the final week of Title 42, and most of them were released to remain in the U.S. at least temporarily as they pursued asylum and legal residency.

With the expiration of Title 42 looming, the Biden administration braced for the possibility of a migrant surge on the southern border. It decided to implement another way to send migrants back to Mexico without the chance to claim asylum — a new policy known as “asylum ineligibility.” If migrants have not tried to claim asylum in the countries they passed through on their way north or have not made appointments for U.S. asylum hearings through the government’s CBP One phone app, they are deemed ineligible to make asylum claims when they cross the border and are sent back south.

The Biden administration has defended using the policy in court, arguing that without it, the numbers could again rise to overwhelming levels. A federal judge in California ruled against the policy, but an appellate court has said the rule can stay in place until it can hear arguments.

So why are a lower percentage of migrants now being turned back?

The Department of Homeland Security did not respond to a request for comment on the decline in expulsions to Mexico.

One reason might be that it simply takes longer to process migrants under the new policy. Under Title 42, migrants did not need to be transferred or see asylum officers to determine whether they had the right to stay in the U.S. and seek legal protection. Now some people either remain in detention or are released into the U.S. while the Biden administration decides whether they are ineligible for asylum. While the new policy results in faster decisions than under the pre-2020 border rules, when many such decisions could take days, it is just not as fast as the expulsion process during the Title 42 era, when decisions could be made in minutes or hours.

Mexico has agreed to take back 30,000 non-Mexican migrants per month from Cuba, Nicaragua, Haiti and Venezuela. Central Americans crossing the border are now growing in number, making it more difficult for Customs and Border Protection to turn them back under the new rule. They may eventually be deported back to their home country, but that process can take much longer.

The drop in expulsions may also be linked to the increased use of the CBP One app. Migrants en route to the U.S. have been able to make appointments for asylum hearings through the mobile app since January, but in recent months the number of users has climbed. In July, CBP One processed more than 44,700 people through appointments made on it, according to CBP data released last week. The majority of migrants who apply through the app are allowed to remain in the U.S. temporarily as they pursue their asylum claims — even though most of them will ultimately lose their cases.

In a statement to NBC News, a DHS spokesperson said that the "asylum ineligibility" policy has led to an overall decline in border crossings.

“The combination of strengthened consequences at the border and expanded lawful pathways has led to a significant reduction in irregular crossings since the end of Title 42,” the DHS spokesperson said.

The spokesperson also pointed out that deportations have risen to make overall removals high.

“The fact is that as of the end June 2023 we have already surpassed fiscal year 2022 removals with more than 195,000 overall since May 12th, including more than 14,000 individual family unit members. This includes over 5,500 nationals of Cuba, Haiti, Nicaragua and Venezuela — the first time in our bilateral history that the government of Mexico has accepted returns at this scale,” the spokesperson said.

Meanwhile, the number of attempted southwest border crossings per day has crept back up from its post-Title 42 low of 3,000 per day to 6,000. And the number of people turned back, though still not at Title 42-era levels, is also rising.

Some shelter operators in Mexico say that while they saw an initial dip after Title 42, the number of migrants returning to their side of the border is starting to rise.

Unlike migrants being pushed back into Mexico under Title 42, migrants sent to Mexico now are less likely to try their luck and cross again because doing so carries the penalty of a felony and prosecution. So shelters in Mexico are seeing a slow increase in numbers from migrants coming back.

“The reality is that we have had more and more people who have been turned back,” said Francisco Bueno, the director of Casa del Migrante in Juárez, Mexico, just across from El Paso, Texas.

This article was originally published on NBCNews.com