Whether NOC was mandatory for foreign trip could be determined after looking into your appointment order/offer letter.  If there's nothing mentioned regarding NOC, then the School has erred in issuing show cause notice to you.  Counter the show cause notice based on your offer letter.

It is not Mandatory to obtain NOC from

private unaided school for going abroad during vacations 

Being employee you are legally duty bound to inform the school authority and to take permission for every our station and foreign visit. Being in employment as such there is no private visit. Summer vacation is not a valid excuse. You are required to give reply to show cause with plausible reasons. 

If your employment offer letter do not mention about obtaining NOC to travel abroad during vacation on a tour or for personal reasons, then it will not be a mandatory requirement for the  private sector employee to obtain NOC from the employer before travelling to abroad.

If your employer has issued a show cause notice, you can give a reply objecting to their notice stating that their notice is illegal because they are acting outside the frame of the school rules and regulations besides contradicting the conditions of employment offer letter and refuse to give any explanation to their notice stating that this is your personal issue to which the employer has no rights to interfere. 

Not mandatory 

Normally, only government servants are required to obtain prior permission from their departments before going on an overseas trip. However, if the service rules of your school stipulate so, you are bound by them. You may explain why you could not get prior permission citing some exigency in a convincing manner and seek condonation.

Dear Client,

If the employment offer letter does not mention obtaining a No Objection Certificate (NOC) for international travel during vacations or for personal reasons, it implies that private sector employees may not be obligated to seek an NOC from their employer before traveling abroad.

If your employer has issued a show cause notice, you can respond by contesting its validity, as it appears to be in violation of both the company's established rules and regulations, as well as the conditions stated in the employment offer letter. Furthermore, you can assert that you decline to provide any explanation, as this matter is strictly personal and beyond the employer's purview.

 - As per law, an NOC is mandatory for a government Employee for travel abroad, however this not applied in case of private school . 

- Further, a teacher in a private non-aided school is neither a public servant or a Govt. Servant and he is purely a private employee, and no rules and procedures like a govt. school is applied in such school. 

- However, if the offer letter signed by you having such restrictions , then it will applied in your case , and if not mentioned then the school cannot dictate you for the NOC , and hence you should reply to the said notice that no such restriction was mentioned in the offer letter and hence it is not mandatory to take NOC before travelling abroad.

You should send a legal notice to the school authorities demanding their authority with the provisions of law to issue show cause notice for this purpose after which you can approach court with a suit to restrain the school authorities to set aside their orders to conduct inquiry on the subject which is contradictory to the law of the land

Your reply to show cause notice was factually incorrect. NOC and permission is necessary under service rules and code of conduct. So school has rightly rejected your reply. On the basis of charge sheet any defense can be suggested. 

Appear before inquiry committee and say there is no such provision that obtaining NOC is mandatory 

Since the offer letter, circulars and notices do not spell out/ silent regarding obtaining NOC in case of going abroad, you couldn't obtain NOC.

The date should be 4 Aug 2023. Please appear at the enquiry and explain to the committee that there is no specific rule which requires getting prior permission. If they insist, ask them to produce the relevant service rule book or circular. In the absence of any such stipulation, tell them you were within your rights in undertaking the overseas trip.

They should not have rejected your response to the show cause notice, without supporting it with any reasons. That's because at this juncture, you do know what is the ground for rejection of your reply to the SCN; and hence,. you cannot effectively represent your case before the inquiry officer.

Consider challenging the rejection order in the High Court. 

- Since, there is no such restriction is mentioned in the offer letter or circular dully signed by you, then they cannot take any legal action against you , only on the ground of NOC not taken prior to travel abroad. 

- You should appear before the committee and produce the agreement /offer letter which you have signed at the time of joining the school 

- You have not committed any offence in the eye of law and haven't even violated the school rules.

You should send a legal notice to the school authorities asking them to provide the legal basis for issuing a show cause notice. If they are unable to provide a valid legal basis, you can file a lawsuit to prevent them from conducting an inquiry into the matter. This is because the inquiry is contradictory to the law of the land.

Yea you can appear alone or with your advocate