Which of the following is most appropriate step of management in a patient who comes to emergency dept with breathlessness and X-ray showing following findings?

Note:- the unilateral left sided hyperlucency devoid of any lung markings suggesting left pneumothorax. Ina small simple pneumothorax, observation alone may be sufficient, while in a more major pneumothorax a chest drain is more effective and safer, paicularly if the patient is symptomatic or has underlying lung disease. In the present case, Plain inseion of intercostal drain/chest tube (X-ray shows left sided pneumothorax).This X-ray shows left sided pneumothorax . There is relative flattening of the left dome and some mediastinal shift to right. Patient has breathlessness and these all features suggest treatment with inseion of intercostal drain.