As a private candidate, you should ensure that your attire is appropriate for a school/examination environment. 

Male private candidates should be in shirt/ collared t-shirts with trousers and should wear covered shoes. Female private candidates should not be wearing revealing or outlandish clothes.

You should also ensure that your hair is cut and dyed back to its natural colour before you sit for your examination.

For Science Practical examinations, it is compulsory for candidates to wear covered shoes and long pants/trousers for safety reasons. 

The attire regulations are specified in the Examination Rules and Regulations for Private Candidates.