When God made this world, why did he let evil exist?

WHY THERE IS EVIL IN THE WORLD, MISCONCEPTION CLEARED.
Because of misunderstanding of the concept of God every person asks this question. This question assumes that SUPERNATURAL OMNIPOTENT EXTERNAL DEITY has the power to do anything and everything we pray for. This in fact was superstitious expression and product of human ignorance, weakness and fear. We need to understand that moral evil is a human creation. Nanak says KARTTOT PASHU KEE MANAS JAT(SGGS page267) meaning in our actions and behaviour we are animals in human skin.
When we understand that God of Guru Nanak is SHABAD GURU, TREASURE OF VIRTUES, and GOD IS EMBODIMENT OF THE UNCHANGEABLE LAWS OF UNIVERSE, a major misconception about why there is evil in the world is cleared. For thousands of years humans believed God is OMNIPOTENT, God has the power of doing any thing and is above the COSMIC LAWS. We assigned this job to ALMIGHTY GOD to solve the problems of the society. Nanak says God is SHABAD GURU, DIVINE WISDOM, DIVINE KNOWLEDGE that guides humans on the journey to be compassionate, tolerant, kind, contented, loving, caring, equal, humble, and spiritually awakened. SHABAD GURU teaches us that we all come from one universal life energy, the essence of life, and that we are one big family of ONE DIVINE MASTER. Any human being with awakened consciousness will not commit evil. We as humans have complete freedom to choose path of evil or empathy, hatred or love, kindness or intolerance. With advancement of knowledge we have both possibilities: the possibility of being God conscious humans or egoistic violent monsters. God does not hold the hand of a rapist; God transforms the rapist to be a protector of women’s honour. It is up to us what kind of next generation we want to raise.
SGGS IS NOT IDOL.
Misunderstanding and misinterpretation of the philosophy of SHABAD GURU, BANI GURU has led Sikhs to worship SGGS as idol. Sikhs today believe in God but do not understand God. That is the reason Sikhs pray in front of the SGGS for gift of son, success in business, victory in elections, court case and thousands of worldly comforts. Because of this ignorance Sikhs fail to understand that birth of boy or girl is determined by genetic combination of X and Y chromosomes. This is the law of nature, WILL OF GOD, HUKM. What Sikhs get out of these prayers is helplessness, anxiety, worries and stress. Further many lose faith in God. Nanak says AISA JUG DEKHIA JUAREE, SABH KICHH MANGAI NAAM BISARI (SGGA page222) meaning humans are playing games with their precious lives every day. They all desire peace, happiness and joy in life but are not prepared to work for it. They can work long hours to earn material wealth but are not ready to meditate on the truthful living, the real source of peace and happiness.
When Sikhs come to understand that God in Gurbani is SHABAD, DIVINE WISDOM, KNOWLEDGE, TREASURE OF VIRTUES, LIVING THE WILL OF GOD, Sikhs will only pray for spiritual guidance, how to be good humans, and realize meaning and purpose of life. Guru says rich is the one who knows the truth.