The stock is being moved from producing states to major consuming centres by trucks and a dedicated railway service called "Kanda Express".
Onions are being sold at a subsidised rate of ₹35 per kg in selected price-sensitive cities.
"Approximately 4,000 tonnes of buffer onion have been sold so far in 17 cities," Khare told PTI on Sunday.
Bulk consignments have already reached Delhi and Chennai through the Kanda Express. A third rake is now being loaded for dispatch to Guwahati in the coming days, she said.
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Government intervention brings some relief
"The distribution of buffer onions has brought some relief to consumers. Prices have fallen slightly," Khare said.
She added that the quality of the government's buffer stock was comparable in size and quality to what private traders were selling.
The move comes after the rabi onion crop, which is usually stored for release later in the year, suffered some damage during harvesting because of untimely rains.
NCCF sells 1,500 tonnes
NCCF Managing Director Anice Joseph Chandra said the federation has sold 1,500 tonnes of buffer onions so far.
"So far, we have sold 1,500 tonnes of buffer onions in different cities across the country. The focus is on retail and selling at Rs 35 per kg," she said.
Several state governments have shown interest in the scheme. NCCF has tied up with some states to sell onions through its stores, mobile vans, cooperative societies and other platforms identified by local administrations.
NCCF's retail intervention is currently under way in Delhi-NCR, Tamil Nadu, Uttar Pradesh, Kerala, Rajasthan, Punjab, Odisha and a few other states.
The Central Warehousing Corporation (CWC), the nodal agency for the operation, is handling the sorting, grading, packing and movement of buffer onions to these states.
Onion prices still high in major cities
According to Chandra, the subsidised sale has led to a ₹2-3 per kg fall in prices.
However, onion prices remain elevated in several cities. Data maintained by the Department of Consumer Affairs showed that the average all-India retail price of onion stood at ₹50.79 per kg, compared with ₹48.5 per kg when the subsidised sale was launched on August 28.
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On September 5, onions were retailing at ₹58 per kg in Delhi, ₹53 per kg in Mumbai, ₹63 per kg in Chennai and ₹40 per kg in Ranchi. The average wholesale price stood at ₹42.79 per kg.
Officials expect prices to ease further when the new kharif onion crop starts arriving in markets from mid-October. They said the outlook for the crop is promising and increased supplies are expected to reduce pressure on prices.