Dear Dinesh,
Leave is a statutory employment benefit available to employees during the course of their employment. However, enjoyment of this benefit is subject to the discretionary sanction of the employer based on exigencies of work. Therefore, leave can never ever be claimed by the employee as a right or privilege.
Coming to your subsequent query, every establishment-specific labor law has its own kinds of leave depending on the nature of activity of the establishment and the scales of such leave are also different from establishment to establishment . For example the Factories Act,1948 and the Plantations Labor Act,1951 provide for only one kind of leave viz., Annual Leave With Wages to their workmen whereas the various Shops and Establishments Acts provide for three types of leave viz., Casual Leave, Sick Leave and Privilege Leave. If you peruse the Working Journalists and Other News Paper Employees Act,1955 and the Sales Promotion Employees Act,1976, you will find, inter alia, Leave on one half of the wages on medical certificate proportionate to the period spent on duty.However, the provisions of the Industrial Employment (Standing Orders) Act,1946 facilitate the fixation and grant of different kinds of leave which are not statutorily available or higher scales of leave by means of incorporation in the standing orders applicable to the establishments through the process of Collective Bargaining.
Coming to the aspect of sanction or refusal of sanction of a leave by the employer, I reiterate that it is the discretion of the employer. However, in case of certain types of leave such as C.L, Sick leave the very name would suggest the occasion for their application unpredictable and Half-pay leave on medical certificate would take away the discretion of the employer. Therefore, an ideal leave sanction procedure needs to be implemented with fairness, flexibility and considerate attitude and not dominated or dictated by rigid workaholic tendency.
As far as I know, every labor law provides the relief in respect of refused E.L to be added to the leave accumulation of the individual. Though it is undeniable that every immediate or hassle-free sanction or arbitrary refusal of leave has its own hidden agenda, certainly, it would reflect the HR practice of an organization. Sorry, I have no idea about any case law in this regard!