If the ongoing fight between CBSE (Central Board of Secondary Education) and the CISCE (Council for the Indian School Certificate Examinations) was to be decided on numbers of schools won over, the battle would long have been over. The CISCE holds onto far fewer schools than the CBSE - both in India and internationally.
Internationally it does make sense to have gone in the direction of CBSE, despite the many strengths of CISCE, if only because given its more prescriptive curricula, and the greater number of schools in India, it is easier for NRIs to return home, and their children to resume studies will considerably less impact. It is one risk of moving and living abroad mitigated...
The CISCE is not a board that is recognised by the Indian government, although as a curriculum and qualification it is widely accepted globally - as if not more so that the CBSE. One reason for this is its focus on English (the CBSE accepts both English and Hindi), and that it is more arts and humanities based. The CBSE is weighed more towards maths, science and engineering.
According to its proponents the CICSE is also tougher and more rigorous in its examinations.
Examinations
The board of the CISCE offers two exams:
ICSE (Indian Certificate of Secondary Education) is an examination that is conducted by the CISCE for the standard 10th.
The subjects have been divided in two parts. Part one consists of courses such as art, socially useful productive work, physical education, education in Moral and Spiritual Values and a third language from at least Class V to VIII class. The candidates are required to have completed these courses.
The second part consists of three groups divided between:
Group 1: Compulsory subjects like English, a second language, History, Civics and Geography
Group 2: Where candidate can opt from any two of the subjects from Mathematics, science, economics, commercial studies, technical drawing, a modern foreign language, a classical language, computer science, environment science and agriculture science
Group 3: Which contains the likes of computer applications, economic application and commercial application, out of which, the student may choose any one of the subjects.
In total 63 subjects are available for students to choose from (although of course schools will not provide all subjects).
In group I and Group 2 the weight of external and internal assessment is in the ratio of 80:20. In group III equal weight is given to both.
ISC
ISC (Indian School Certificate) is an examination that conducted by the Council for the Indian School Certificate Examinations for Grade 12.
The subjects of examination includes English as a compulsory subject and a list of elective subjects.
The list of electives contains subjects like: geography, sociology, history, physics, biology, chemistry, home science, etc. Some 50 subjects are offered by the CISCE in total.
All candidates are examined in English. The result of the Indian School Certificate is based on external examinations at the end of Class XII.
Note, it seems pretty difficult not to pass either the ISC or ISCE. In 2016 98.50% of students passed the ISCE and 96.46% passed the ISC. Students and schools differentiate themselves on how well they pass.