data/spatial_aggregation/jo_9hx8w.py

def true_code():
    import pandas as pd
    df = pd.read_csv('raw_data/main_data.csv')
    df['Timestamp'] = pd.to_datetime(df['Timestamp'])
    data = df[(df['Timestamp'].dt.day == 26) & (df['Timestamp'].dt.month == 1)].groupby('state')['PM2.5'].mean().idxmax()
    print(data)

true_code()