The Britain-based monitor said more than 20,000 people had fled to western neighbourhoods of the city held by the government, with another 30,000 moving to areas held by Kurdish forces.
Syrian troops have seized at least a third of eastern Aleppo since renewing their bid to recapture all of the battered second city just over two weeks ago.
The former rebel stronghold has been under a government siege for more than four months, with international aid rations exhausted and other food stocks dwindling.
Many have chosen to go from the east to neighbourhoods held by Kurdish forces, which are officially aligned with neither the regime nor rebels, such as Sheikh Maqsud in the city's north.
Once Syria's economic powerhouse, Aleppo has been ravaged by the conflict that began with anti-government protests in March 2011.
The rebel-held east, which fell from government control in 2012, has been particularly savaged by the conflict, with widespread destruction caused by repeated regime attacks.
The loss of east Aleppo would be potentially the worst blow for rebel forces since the conflict began.
Disclaimer: No Business Standard Journalist was involved in creation of this content
You’ve reached your limit of {{free_limit}} free articles this month.
Subscribe now for unlimited access.
Already subscribed? Log in
Subscribe to read the full story →
Smart Quarterly
₹900
3 Months
₹300/Month
Smart Essential
₹2,700
1 Year
₹225/Month
Super Saver
₹3,900
2 Years
₹162/Month
Renews automatically, cancel anytime
Here’s what’s included in our digital subscription plans
Access to Exclusive Premium Stories
Over 30 subscriber-only stories daily, handpicked by our editors


Complimentary Access to The New York Times
News, Games, Cooking, Audio, Wirecutter & The Athletic
Business Standard Epaper
Digital replica of our daily newspaper — with options to read, save, and share


Curated Newsletters
Insights on markets, finance, politics, tech, and more delivered to your inbox
Market Analysis & Investment Insights
In-depth market analysis & insights with access to The Smart Investor


Archives
Repository of articles and publications dating back to 1997
Ad-free Reading
Uninterrupted reading experience with no advertisements


Seamless Access Across All Devices
Access Business Standard across devices — mobile, tablet, or PC, via web or app