International law

All the research that includes human population as study sample needs ethical clearance and the consent as well. Unless the research project is reviewed by an independent and competent body, "no sensitive private data asked. " remains the opinion of researchers only. However, if the research project qualifies as multi-center project, as per the established guidelines (WHO and other universal guidelines) it may need permission from competent bodies (gatekeepers) of the targeted research locations, if not full ethical approval. Researchers are required to consider the ethical risk of any procedure within a research project which involves human participants or personal data, consulting the relevant Faculty, Department, School, and University policies and personnel, before any work is undertaken. Ethical procedures are compulsory for research involving humans and animals, digitally or not. 
The surveyor or researcher will need ethics approval in all countries, you will probably need authenticated translations of your survey in all the languages used, you will need to evaluate the internal and external validity of the questionnaire, find the test retest reliability for each language version of the questionnaire, at the least.

There are 3 regulations one should abide by-
1.Institutional
2.Publisher
3.Government regulations
If approval from any of the above is obtained then ethical review board approves it.

More studying material - https://www.who.int/ethics/Ethics_basic_concepts_ENG.pdf

Best Regards