Human Geography
Tel Aviv is not the capital of Israel and is by far the least religious location in Israel, but has the highest percentage of Jewish residents. Tel Aviv, despite swallowing up the Arab city of Jaffa, contains very few Arabs. In most Israeli cities this difference would be quite noticeable, but the city is extremely secular. In fact, Tel Aviv resembles any western city so much that it might be deemed "ordinary". This, in fact, is exactly what the Zionists wanted to achieve; a place where Jews could be ordinary people. Workers in Jerusalem often commute to work and live in Tel Aviv. Many Jews prefer the night-life and modernity of Tel Aviv to Jerusalem, where Heredim bustle to and from the synagogue.
This is not to say that Jews in Tel Aviv are not Jewish, there are some Heredim and most Jews in Tel Aviv practice Judaism in some form or another. It's just a more relaxed sense of religion than can be found in many other middle-eastern cities.
In fact, the founding and development of Tel Aviv have caused its condition as the most Jewish city in Israel. It was started on land that did not belong to anyone else, for Jews to be lived in by Jews. In fact, it holds the same character the original founders wished it to have, with Zionist intentions.
The map above shows the slow acquisition of land by the Jews during the
Israeli War of Independence. Keep in mind that on May 14, 1948, Israel
became an independent state. At this time, Tel Aviv was already entirely
owned by Jews and the areas around it represent the earliest land claims
by Jews. Since Israel was so intensely segregated by religion for so many
years, land ownership is the best determinant of today's demographic.