The "PDT" policy was initially approved by FINRA (Financial Industry Regulatory Authority) in 2001 in order to protect investors from big losses. Pattern Day Trading's main rule is that in order for a trader to engage in pattern day trading he must maintain an equity balance of at least $25,000 in a margin account.
While some brokers, might apply the "PDT" rule (pattern day trading), it will not apply to your account with Trading 212.