"Aamir does not study in the morning."
Translation:आमिर सुबह नहीं पढ़ता है।
It is not wrong per se but the postposition is usually omitted. Confusingly, this is not done for other times of the day like दोपहर (afternoon), शाम(evening) or रात(night) where को or में is compulsorily used. Just a quirk of the language.