Summer solstice is the longest day of the year. It falls between June 20 and June 22 in the northern hemisphere. This year, in 2023, the longest day of the year falls on June 21, 2023. Same is true for Pakistan and rest of many countries.
Other such day is winter solstice, that is the smallest day of the year. That falls on the Dec 22, 2023 this year in Pakistan.
On the summer solstice the area where it is applicable, that experiences the most amount of sunlight in the year and opposite is true for the winter solstice. Naturally the night of the summer solstice day is the shortest. Opposite is true for the nights around the winter solstice.
Summer solstice itself is observed two times in a year in different parts of earth. Once in the Northern Hemisphere somewhere between June 20 and 22 and other time in the Southern hemisphere around Dec 22. So amazingly both the summer solstice days in northern and southern hemisphere are very much apart.