Here is my weekly halachah column for Sukkos:
The Torah reading for Shemini Atzeres (Devarim 16:13) contains the commandment: “chag ha’Sukkos ta’aseh lecha shivas yamim” (You shall make the festival of Sukkos for a seven day period). The Talmud understands the word lecha to mean that a sukkah must be one’s own: R. Eliezer rules that one cannot fulfill the mitzvah with a borrowed sukkah, just as one one cannot fulfill the mitzvah of taking the four species (on the first day of Sukkos) with a borrowed lulav, while the other Sages allow a borrowed sukkah, and explain that the word lecha teaches only that a stolen sukkah is invalid. (Sukkah 27b)
The halachah follows the view of the Sages. Furthermore, the Talmud explains that due to the principle that “real property cannot be stolen,” a sukkah built in a public space is valid and not considered a “stolen sukkah,” since the land itself does not have the status of stolen property. (Ibid. 31a) Nevertheless, early halachic authorities rule that it is still improper ab initio to build a sukkah on public property. (See Darkei Moshe OC 637) Some authorities go so far as to maintain that a blessing may not be recited upon such a sukkah, since it is tainted by theft. (Magen Avraham ibid. #3) Others, however, are more lenient, arguing that building a sukkah for the limited duration of the holiday, after which it will be removed, does not constitute theft, and that since the members of the public, or the governmental authorities, observe the erection of sukkos and do not object, this constitutes tacit permission for their construction. (See the sources cited in Biur Halachah ibid. s.v. V’chein b’karka)
Regarding building a sukkah on private property but in violation of the law, R. Yosef Shalom Elyashiv (discussing aesthetic zoning regulation) is reported to have ruled that this should not be done. (Chashukei Chemed Sukkah pp. 239-40) On the other hand, R. Asher Weiss (discussing building safety regulation) inclines to the view that there is no need to strictly obey the letter of the law insofar as there is absolutely no danger entailed in ignoring it, and since the authorities observe the construction of numerous sukkos and make no effort to enforce the law, the fact that they are technically illegal does not matter. (Shut. Minchas Asher 2:123)
A Reading Responsa lecture of mine on this topic, with accompanying handout, is available at the Internet Archive.