The article discusses the challenges facing affordable housing projects due to high costs and rising interest rates.  Developers are struggling to complete below-market rental projects, leading to significant financing gaps and delays.  For example, the Fiesta Trails Apartments in San Antonio saw costs rise from $8 million to nearly $11 million due to inflation and interest rate hikes.  The Viento Apartments faced similar issues, with per-unit costs increasing from $110,000 to $151,000.  These challenges are causing a decrease in new affordable housing projects, with a significant drop expected by 2025.  Local governments are using federal pandemic relief funds to bridge financing gaps, but these funds are limited and will soon run out.