Mexico City - For Oscar-winning director Alfonso Cuarón, returning to film in his native Mexico was an itch that took 16 years to finally scratch.

Ever since Cuarón found international success with the movie Y Tu Mama Tambien, commitment after commitment, among them Children of Men and Gravity, delayed his plans for a more personal project back home.

"Movies are like a cereal box - at the bottom there is the promise of a toy," Cuarón said Tuesday at a news conference in the Mexican capital, paraphrasing friend and colleague Guillermo del Toro to describe why he filmed his latest in Mexico.

"Gravity was that cereal box and I got that little toy, which usually leads to a bigger film with more production, with more stars," Cuarón told reporters. "But I decided to return to Mexico City to make this movie with the resources I had always dreamed about."

Cuarón has now wrapped shooting on "Roma," a 1970s period piece about a year in the life of a middle-class family that is infused by the director's experiences as a child and his Mexican identity.

"I can live abroad, but my head keeps thinking in Mexican, in 'chilango,'" Cuarón said, employing a local slang referring to denizens of the capital. "I am very much up on the happenings of my country, and I miss where I am from."

Cuarón, who kept quiet on details of the plot of Roma, was accompanied by production designer Eugenio Caballero, who won an Academy Award for his work on Pan's Labyrinth and is art director for the new film.

Both thanked Mexico City authorities and apologized to locals for the inconvenience of shutting down several main streets. Among those was a thoroughfare where they recreated the 1971 Corpus Christi Massacre of dozens of student protesters by a paramilitary group known as Los Halcones, or "The Hawks."

"We weren't thinking about this frivolously," Cuarón said. "We did this to re-create a historic moment in Mexicans' consciousness. ...For that very reason it was essential to film this scene where the events actually happened.

"By the nature of the project, being a period film, we had to close streets," Caballero said. "In addition to the support from the authorities, the people understood what the project was about and it was interesting to talk about that city for which many people were stirred by nostalgia."

Cuarón, whose credits also include A Little Princess, Great Expectations and Harry Potter and the Prisoner of Azkaban, will spend the rest of the year on post-production for Roma ahead of its expected premier in 2018.