The employer cannot withhold your salary. You have been on sick leave after taking proper permission from the employer. There is no fault from your side and you have not committed a breach of contract.
Your employer knows that you are ailing hence, he must release your salary for the period to which you have worked for him. According to Section 2(s) of the Payment of Wages Act, the term salary or wages means all emoluments which are earned by an employee while on duty or on leave in accordance with the terms and conditions of his employment.
You have earned your salary and the employer benefited from your work. It is thus responsible of your employer to make payment of all wages required to be paid under the work agreement. Your salary is not a bounty and the employer cannot exercise his discretion to pay or withhold your salary.
Send a legal notice to the employer for payment of salary
You should immediately send a legal notice to the employer and demand your salary. If he denies or does not reply to your notice within a reasonable time then you should file a complaint before the Industrial Tribunal.
Delivery of inventories is a separate issue and it does not relate with the payment of wages. You are still his employee because the employer did not terminate your service. Therefore, he cannot withhold your salary in lieu of office inventory.