title: Python: How to drop a row whose particular column is empty/NaN?
body: <p>I have a csv file. I read it:</p>
  
  <pre><code>import pandas as pd
  data = pd.read_csv('my_data.csv', sep=',')
  data.head()
  </code></pre>
  
  <p>It has output like:</p>
  
  <pre><code>id    city    department    sms    category
  01    khi      revenue      NaN       0
  02    lhr      revenue      good      1
  03    lhr      revenue      NaN       0
  </code></pre>
  
  <p>I want to remove all the rows where <code>sms</code> column is empty/NaN. What is efficient way to do it?</p>