Rising on-chain transaction fee ratios often signal increased network congestion risk. Higher fees indicate more users are competing for limited block space, driving up costs to prioritize transactions. This can lead to slower confirmations and reduced network efficiency, especially during peak demand. For example, Bitcoin and Ethereum have historically seen fee spikes during bullish markets or major events like NFT mints. However, fee increases don't always mean congestion; they can also reflect growing adoption or complex transactions requiring more data. Monitoring metrics like mempool size, confirmation times, and fee rates helps assess true congestion risk. Scalability solutions like Lightning Network or layer-2 rollups aim to mitigate these issues by offloading transactions. Still, persistent high fee ratios warrant caution, as they may deter users and strain network performance.