Which of the following tributaries is not part of the Indus river system?

Which of the following tributaries is not part of the Indus river system?

مندرجہ ذیل میں سے کون سا علاقہ دریائے سندھ کے نظام کا حصہ نہیں ہے؟
Explanation

Porali River is not a part of the Indus River system; it flows in Balochistan and drains into the Arabian Sea separately.

Bolan, Chenab, and Panjkora are all tributaries of the Indus River system in Pakistan.