When dealing with a situation where your foreign supervisor is not responding to your emails, it's important to approach the matter professionally and politely. Here's a suggested email you can send to gently remind them:

Subject: Gentle Reminder: [Topic/Subject of the email]

Dear [Supervisor's Name],

I hope this email finds you well. I wanted to follow up on the email I sent on [date] regarding [topic/subject]. I understand that you may be busy with other priorities, but I wanted to ensure that my message reached you.

I would greatly appreciate it if you could spare a few moments to review my previous email and provide any necessary feedback or guidance. Your input is crucial for me to proceed with the project/task at hand.

Please let me know if there is anything else I can do to assist you or if you require any additional information from my end. I look forward to hearing from you soon.

Thank you for your attention and support.

Best regards,
[Your Name]

Remember to remain respectful and professional in your communication. If you still don't receive a response after sending a gentle reminder, it may be appropriate to seek alternative methods of communication, such as scheduling a meeting or reaching out through other channels if available.