On June 10, it was announced that Baekhyun will debut as a solo artist in July 2019. On June 20, the title of the EP City Lights was revealed, and the release date July 10. On the same day, the pre-order for the two versions "Day" and "Night" of the EP started. On June 21, it was revealed that Baekhyun will collaborate with rapper Beenzino for the track "Stay Up". On July 2, two teaser images of the EP were released along with a concept film video. On the same day, it was revealed that the title track is titled "UN Village", described as a romantic love song. On July 3, additional two teaser images were released and the EP details. On July 4, the list of the EP's producers was revealed, having world-renowned music producer Darkchild, The Stereotypes, Cha Cha Malone, LDN Noise and others. On July 5, the first teaser of the music video was released. On July 6, four additional teaser images were released. On July 7, another four teaser images were released. On July 8, a highlight medley of the tracks was released. On July 9, additional three photo teasers were released. On July 11, Behind clip of "UN Village" music video was released through Baekhyun's official YouTube channel as a vlog. On the same day, it was revealed that a third version "Kihno" of the album will be released on July 19. On July 12, live session video of "UN Village" was released. On July 12-14, a jacket making film for the two versions of the EP were released through Exo's official social media accounts. On July 15, Baekhyun 's "UN Village" music video commentary videos were released. On July 16 and 17, "UN Village" music video close up cam videos were released. On the same days, "UN Village" music video behind photos were released. On July 20, "UN Village" music video behind was released.
"UN Village" is a romantic R&B love song that combines groovy beats and string sound with sensational lyrics about a romantic moment a couple share under the moonlight of UN Village hill. "Stay Up" is a dreamy R&B song featuring Rapper Beenzino with lyrics that draws attention by mentioning special nights with his loved one in sexy narratives. "Betcha" is described as an Hip hop R&B with urban beats song with lyrics that tells a story about a cute yet confident attitude of a man who is confident that the other person is destined for love. "Ice Queen" is an R&B song with a sophisticated beat and a catchy melody with lyrics about winning the girls' cold heart with his warm one. "Diamond" is an R&B ballad with impressive major and minor melodies with the lyrics that compare love for lovers to a solidly glowing diamond. "Psycho" is an electronic pop that expresses the inner selves of a man lost among confused emotions.
On July 10, Baekhyun held a private showcase for City Lights in Seoul Arts Center where he performed "UN Village" for the first time for the media, before the EP's release. On the same day, he held a showcase for the fans where he talked about the process of the album and performed "UN Village", "Betcha" and "Ice Queen".
Baekhyun started performing "UN Village" on South Korean music show from July 12 on Music Bank.
On July 23, Baekhyun will hold a fan-sign event in Samsong-dong at SMTOWN COEX Artium 5F Theater. On July 31, the singer will hold a fan-sign event at Ilchi Art Hall in Apgujeong-dong.
On July 9, it was reported that the pre-order sales of City Lights reached 401,545 copies in eight days, making it the best-selling solo album in South Korea since 7th Issue (2004) by Seo Taiji. The EP, sold 1,000 copies in the United States according to Nielsen Music, despite less than two full days of sales for the Billboard week's charts.