The director of the Population Division of the Department of City Planning, Joseph Salvo, talked last week with The New York Sun’s Daniela Gerson about the city’s record 2.9 million foreign-born residents. Mr. Salvo is an author of the fourth edition of the “Newest New Yorkers,” a report released last week, which provides a detailed record of how immigrants fueled the growth in the city’s population in the 1990s from 7.3 million residents to more than 8 million.

Q. You have been with the Department of City Planning for 22 years. When did you know you were onto an immigration boom?

A. I got here at a point where we started to see the important effects of immigration. I remember two meetings that were very interesting and very useful from my perspective now.

One involved the schools. We had large numbers of immigrants beginning to come in and at that time the school system was talking about declining enrollment. … I remember saying at that time, “We better watch it, because we’ve got this immigration, and we think that immigration is associated with higher fertility rates, “and, lo and behold, shortly after that we began to see school enrollments starting to take off.

The other meeting was with the Transit Authority. The Transit Authority was thinking about taking down one of the elevateds in the Bronx because of the lack of use, and [a colleague] and I said to them, “Let’s wait a little bit on that, we think something might be coming down the road here.” … I’m happy to say years later whoever made that decision not to take down that elevated in the Bronx, not to remove that infrastructure, made a very wise choice because we all know how well used the elevateds in the Bronx are.

In the late ’80s the director of the division and I said we really need to start a kind of ongoing chronicle of immigration in New York because it is important now, and we expect it to become more important as time goes on.

What were the biggest surprises in this most recent report?

Currently 43% of our immigration is post-1990, which is what this is all about … but most groups managed to come up with a median household income near the city’s average despite the fact that they just got here. It’s pretty amazing….

Geographically the biggest surprise is the emergence of this swath along southern Brooklyn, starting with Sunset Park, the Hispanics on one side down the hill, and up the hill the Chinese, then over into the Arabs in Bay Ridge. Let’s not forget Borough Park over to the east, moving down through Bensonhurst where the Chinese have gone and now the Russians have come up. And then probably one of the most interesting places in the city, the Midwood-Flatbush community district, that goes from Bensonhurst up to the park: In there you will see Pakistanis, you will see refugees from Southeast Asia up north, you will see Dominicans, Mexicans, Afro-Caribbeans, all kind of converging there. And then you move into Gravesend-Homecrest, Flatlands-Canarsie and you transition into Chinese and Russian, and a whole lot of Afro-Caribbean groups that have moved in there in the past 10 years.

How has the role of immigrant labor changed in the past two decades?

What has happened is the city has come to rely on immigrant labor in a major way. It still surprises me how dominant immigrants still are in some industries in the city, 60% of manufacturing workers, over one-half of workers in construction. You can’t go into a hospital or even a school without finding an immigrant employee. That was another surprise, the participation of immigrants in the schools was much higher than we thought. Five-hundred-fifty-thousand immigrants are in service – like 48% to 49% of all workers in the industry. Then think about all the entrepreneurs, from nail salons to laundries to fruit sellers, these are all the stories we have.

How has national immigration policy affected the inflows of immigrants into New York?

In the late 1980s we had an exciting period where immigrants were granted amnesty nationwide. It turns out in New York the number was only about 140,000. In California it was in the millions, because Mexicans were the largest group receiving benefits from the amnesty, part of the Immigration Reform and Control Act. As it turns out, in the 1990s several of our bigger immigrant groups received the benefit from the Immigration Reform and Control Act. The Mexicans that were here received amnesty, and their relatives started to come in the 1990s and form communities that then served as a base for further immigration.

A spin-off from the IRCA legislation was the diversity visa – the lottery visas – because there were groups, many of them were here in New York, Poles and Irish especially, that did not qualify for amnesty under the rules of IRCA. And then these diversity lottery visas caused a surge in Irish immigration. The Poles were also able to take advantage of those visas, and, the biggest surprise, the Bangladeshis started to take those visas. All these groups became players in the 1990s. The Irish tailed off because conditions in Ireland became better and because they lost their special allocation of diversity visas. The Bangladeshi rose and the Polish immigration has maintained itself.

The other big news in the late ’80s was the fall of the former Soviet Union. We had received Russians in the late ’70s, but now in the late ’80s there was this tremendous push out of the former Soviet Union. We started to see Russians come in. The face of immigration was changing again in New York. What we didn’t realize at the time was that what had started out, these lottery visas, essentially as a favor to a series of groups that were disadvantaged as a result of the Immigration Reform and Control Act, turned out to truly diversify immigration in the city. To this day it has given groups that would otherwise not be able to come in opportunities to immigrate, most recently immigrants from Nigeria and Ghana.

The 1970s was the last time immigrant New York was dominated by just one continent, Europe. Do you see a single region of origin dominating immigrant New York again in the future?

No. That’s an easy question. If anything our continent mix has actually gotten more balanced. … Every year we seem to get a new country, Egypt, Yemen, the former Yugoslavia. All these communities represent a broader continental mix, and I expect that to continue. I would call it a progression to a real world city.

How many languages are spoken in the city?

The answer to the question is, using the current tools we have available, 175 to 200. Which is huge.

Is that the most of any city in America?

I would venture to say, yes, by the representation of immigrants here. We’re talking about 1.5 million people 18 and older who have problems with English. Half of those people speak Spanish, and then large contingents follow from China, Russia, and a whole slew of other countries.

Have you noticed a decrease in immigrants coming to the city after 9/11?

We have no evidence that immigration has declined.

What is the downside to all this immigration and population growth?

Well, the truth is we have overcrowding issues, we have growth management issues that are pretty serious. We have housing shortage issues. But think about those problems and think about the problems they have in other cities: Issues of how to tear down whole blocks of buildings because they’ve been abandoned; Issues of what to do with a neighborhood that has been abandoned and the buildings are falling down and pose a safety issue.